Add type relationship functions to checker api

.mailmap

@@ -1,13 +1,14 @@
 
 AbubakerB <abubaker_bashir@hotmail.com> # Abubaker Bashir
 Alexander <alexander@kuvaev.me># Alexander Kuvaev
+Aluan Haddad  <aluanh@gmail.com>
 Adam Freidin <adam.freidin@gmail.com> Adam Freidin <afreidin@adobe.com>
 Adi Dahiya <adahiya@palantir.com> Adi Dahiya <adi.dahiya14@gmail.com>
 Ahmad Farid <ahfarid@microsoft.com> ahmad-farid <ahfarid@microsoft.com>
 Alexander Rusakov  <a_s_rusakov@mail.ru>
 Alex Eagle <alexeagle@google.com>
 Anatoly Ressin  <anatoly.ressin@icloud.com>
-Anders Hejlsberg <andersh@microsoft.com> unknown <andersh@AndersX1.NOE.Nokia.com> unknown <andersh@andersh-yoga.redmond.corp.microsoft.com>
+Anders Hejlsberg <andersh@microsoft.com> unknown <andersh@AndersX1.NOE.Nokia.com> unknown <andersh@andersh-yoga.redmond.corp.microsoft.com> Anders Hejlsberg  <Anders Hejlsberg>
 about-code  <about-code@users.noreply.github.com> # Andreas Martin
 Andrej Baran  <andrej.baran@gmail.com>
 Andrew Ochsner  <andrew.ochsner@wipro.com>
@@ -24,6 +25,7 @@ Basarat Ali Syed <basaratali@gmail.com> Basarat Syed <basaratali@gmail.com> basa
 Bill Ticehurst <billti@hotmail.com> Bill Ticehurst <billti@microsoft.com>
 Ben Duffield <jebavarde@gmail.com>
 Ben Mosher  <me@benmosher.com>
+Benjamin Bock  <bb@users.noreply.github.com>
 Blake Embrey <hello@blakeembrey.com>
 Bowden Kelly <wilkelly@microsoft.com>
 Brett Mayen <bmayen@midnightsnacks.net>
@@ -49,6 +51,7 @@ Dirk Holtwick <dirk.holtwick@gmail.com>
 Dom Chen  <domchen@users.noreply.github.com>
 Doug Ilijev <dilijev@users.noreply.github.com>
 Erik Edrosa <erik.edrosa@gmail.com>
+Erik McClenney  <erikmcc@google.com>
 erictsangx  <erictsangx@gmail.com> # Eric Tsang
 Ethan Rubio <ethanrubio@users.noreply.github.com>
 Evan Martin <martine@danga.com>
@@ -68,13 +71,18 @@ Guillaume Salles <guillaume.salles@me.com>
 Guy Bedford <guybedford@gmail.com> guybedford <guybedford@gmail.com>
 Harald Niesche <harald@niesche.de>
 Homa Wong  <homawong@gmail.com>
+Hendrik Liebau  <mail@hendrik-liebau.de>
 Iain Monro <iain.monro@softwire.com>
+IgorNovozhilov  <maildrakon@gmail.com> # Igor Novozhilov
 Ingvar Stepanyan <me@rreverser.com>
 impinball <impinball@gmail.com> # Isiah Meadows
+Iwata Hidetaka  <iwata0303@gmail.com>
 Ivo Gabe de Wolff <ivogabe@ivogabe.nl>
 Jakub Młokosiewicz  <hckr@users.noreply.github.com>
 James Whitney <james@whitney.io>
+James Henry  <james@henry.sc>
 Jason Freeman <jfreeman@microsoft.com> Jason Freeman <JsonFreeman@users.noreply.github.com>
+Jason Jarrett  <jason@elegantcode.com>
 Jason Killian <jkillian@palantir.com>
 Jason Ramsay <jasonra@microsoft.com> jramsay <jramsay@users.noreply.github.com>
 Jed Mao <jed.hunsaker@gmail.com>
@@ -89,6 +97,7 @@ Jonathan Toland <toland@dnalot.com>
 Jesse Schalken <me@jesseschalken.com>
 Joel Day  <joelday@gmail.com>
 Josh Abernathy  <joshaber@gmail.com> joshaber  <joshaber@gmail.com>
+Josh Goldberg  <joshuakgoldberg@outlook.com>
 Josh Kalderimis <josh.kalderimis@gmail.com>
 Josh Soref <jsoref@users.noreply.github.com>
 Juan Luis Boya García <ntrrgc@gmail.com>
@@ -107,20 +116,26 @@ Keith Mashinter <kmashint@yahoo.com> kmashint <kmashint@yahoo.com>
 Ken Howard <ken@simplicatedweb.com>
 Kevin Lang  <klang2012@gmail.com>
 kimamula <kenji.imamula@gmail.com> # Kenji Imamula
+Kitson Kelly  <me@kitsonkelly.com>
 Klaus Meinhardt  <klaus.meinhardt1@gmail.com>
 Kyle Kelley <rgbkrk@gmail.com>
 Lorant Pinter <lorant.pinter@prezi.com>
 Lucien Greathouse <me@lpghatguy.com>
 Lukas Elmer  <lukas.elmer@gmail.com> Lukas Elmer  <lukas.elmer@renuo.ch>
+Magnus Hiie  <magnus.hiie@gmail.com>
 Martin Vseticka <vseticka.martin@gmail.com> Martin Všeticka <vseticka.martin@gmail.com> MartyIX <vseticka.martin@gmail.com>
 gcnew  <gcnew@abv.bg> # Marin Marinov
 vvakame <vvakame+dev@gmail.com> # Masahiro Wakame
-Matt McCutchen <rmccutch@mit.edu>
+Matt McCutchen <rmccutch@mit.edu>  Matt McCutchen  <matt@mattmccutchen.net>
+Matt Bierner  <matb@microsoft.com>
 MANISH-GIRI  <manish.giri.me@gmail.com> # Manish Giri
 Max Deepfield <maxdeepfield@absolutefreakout.com>
 Micah Zoltu <micah@zoltu.net>
 Michael  <maykelchiche@gmail.com>
+Mike Busyrev  <busyrev@gmail.com>
+Mine Starks  <minestarks@users.noreply.github.com> Mine Starks  <mineyalc@microsoft.com>
 Mohamed Hegazy <mhegazy@microsoft.com>
+ncoley  <nrcoley@gmail.com> # Natalie Coley
 Nathan Shively-Sanders <nathansa@microsoft.com>
 Nathan Yee <ny.nathan.yee@gmail.com>
 Nima Zahedi <nima.zahedee@gmail.com>
@@ -143,19 +158,22 @@ Rado Kirov <radokirov@google.com>
 Ron Buckton <rbuckton@microsoft.com> Ron Buckton <ron.buckton@microsoft.com> rbuckton  <rbuckton@chronicles.org>
 Rostislav Galimsky  <rostgal@gmail.com>
 Richard Knoll <riknoll@users.noreply.github.com> Richard Knoll <riknoll@microsoft.com>
+Richard Karmazín  <richard@karmazin.cz>
 Rowan Wyborn <rwyborn@internode.on.net>
 Ryan Cavanaugh <RyanCavanaugh@users.noreply.github.com> Ryan Cavanaugh <ryan.cavanaugh@microsoft.com> Ryan Cavanaugh <ryanca@microsoft.com>
 Ryohei Ikegami <iofg2100@gmail.com>
 Sarangan Rajamanickam <sarajama@microsoft.com>
 Sébastien Arod <sebastien.arod@gmail.com>
 Sergey Shandar  <sergey-shandar@users.noreply.github.com>
+chico  <chi187@gmail.com> # Sergey Rubanov
 Sheetal Nandi <shkamat@microsoft.com>
 Shengping Zhong <zhongsp@users.noreply.github.com>
 shyyko.serhiy@gmail.com <shyyko.serhiy@gmail.com> # Shyyko Serhiy
 Sam El-Husseini  <samelh@microsoft.com>
 Simon Hürlimann <simon.huerlimann@cyt.ch>
 Slawomir Sadziak  <slsadzia@microsoft.com>
 Solal Pirelli <solal.pirelli@gmail.com>
+Soo Jae Hwang  <misoguy1985@gmail.com>
 Stan Thomas <stmsdn@norvil.net>
 Stanislav Sysoev <d4rkr00t@gmail.com>
 Steve Lucco <steveluc@users.noreply.github.com> steveluc <steveluc@microsoft.com>
@@ -173,6 +191,7 @@ Torben Fitschen  <torben.fitschen@mayflower.de>
 TruongSinh Tran-Nguyen <i@truongsinh.pro>
 vilicvane <i@vilic.info> # Vilic Vane
 Vladimir Matveev <vladima@microsoft.com> vladima <vladima@microsoft.com> v2m <desco.by@gmail.com>
+Vadi Taslim  <vadz77@hotmail.com>
 Wesley Wigham <t-weswig@microsoft.com> Wesley Wigham <wwigham@gmail.com>
 York Yao <plantain-00@users.noreply.github.com> york yao <yaoao12306@outlook.com> yaoyao <yaoyao12306@163.com>
 Yuichi Nukiyama <oscar.wilde84@hotmail.co.jp> YuichiNukiyama <oscar.wilde84@hotmail.co.jp>
@@ -199,6 +218,7 @@ Aliaksandr Radzivanovich <aradzivanovich@gmail.com>
 BuildTools <FranklinWhale@users.noreply.github.com> # Franklin Tse
 ChogyDan <danielhollocher@gmail.com> # Daniel Hollocher
 Daniel Rosenwasser <DanielRosenwasser@users.noreply.github.com> Daniel Rosenwasser <drosen@microsoft.com>
+DLehenbauer  <DLehenbauer@users.noreply.github.com> # Daniel Lehenbauer
 David Kmenta <david.kmenta@lmc.eu>
 E020873 <nicolas.henry-partner@arcelormittal.com> # Nicolas Henry
 Elisée Maurer <elisee@sparklinlabs.com>
@@ -225,4 +245,7 @@ Viktor Zozulyak <zozulyakviktor@gmail.com>
 rix <rix@rixs-MacBook-Pro.local> # Richard Sentino
 rohitverma007 <rohitverma@live.ca> # Rohit Verma
 rdosanjh  <me@rajdeep.io> # Raj Dosanjh
-gdh1995  <gdh1995@qq.com> # Dahan Gong
+gdh1995  <gdh1995@qq.com> # Dahan Gong
+cedvdb  <cedvandenbosch@gmail.com> # @cedvdb
+kpreisser  <kpreisser@users.noreply.github.com> # K. Preißer
+e-cloud  <saintscott119@gmail.com> # @e-cloud

AUTHORS.md

@@ -10,6 +10,7 @@ TypeScript is authored by:
 * Alexander Rusakov 
 * Ali Sabzevari
 * Aliaksandr Radzivanovich
+* Aluan Haddad 
 * Anatoly Ressin 
 * Anders Hejlsberg
 * Andreas Martin
@@ -29,13 +30,15 @@ TypeScript is authored by:
 * Basarat Ali Syed
 * Ben Duffield
 * Ben Mosher 
+* Benjamin Bock 
 * Bill Ticehurst
 * Blake Embrey
 * @bootstraponline
 * Bowden Kelly
 * Brett Mayen
 * Bryan Forbes
 * Caitlin Potter
+* @cedvdb
 * Charly POLY 
 * Chris Bubernak
 * Christophe Vidal 
@@ -49,6 +52,7 @@ TypeScript is authored by:
 * Dan Corder
 * Dan Quirk
 * Daniel Hollocher
+* Daniel Lehenbauer
 * Daniel Rosenwasser
 * David Kmenta
 * David Li
@@ -60,10 +64,12 @@ TypeScript is authored by:
 * Dirk Holtwick
 * Dom Chen 
 * Doug Ilijev
+* @e-cloud
 * Elisée Maurer
 * Emilio García-Pumarino
 * Eric Tsang
 * Erik Edrosa
+* Erik McClenney 
 * Ethan Resnick 
 * Ethan Rubio
 * Evan Martin
@@ -84,15 +90,20 @@ TypeScript is authored by:
 * Guillaume Salles
 * Guy Bedford
 * Harald Niesche
+* Hendrik Liebau 
 * Herrington Darkholme
 * Homa Wong 
 * Iain Monro
+* Igor Novozhilov
 * Ingvar Stepanyan
 * Isiah Meadows
 * Ivo Gabe de Wolff
+* Iwata Hidetaka 
 * Jakub Młokosiewicz 
+* James Henry 
 * James Whitney
 * Jason Freeman
+* Jason Jarrett 
 * Jason Killian
 * Jason Ramsay
 * JBerger
@@ -110,38 +121,46 @@ TypeScript is authored by:
 * Jonathan Turner
 * Jonathon Smith
 * Josh Abernathy 
+* Josh Goldberg 
 * Josh Kalderimis
 * Josh Soref
 * Juan Luis Boya García
 * Julian Williams
 * Justin Bay 
 * Justin Johansson 
+* K. Preißer
 * Kagami Sascha Rosylight
 * Kanchalai Tanglertsampan
 * Keith Mashinter
 * Ken Howard
 * Kenji Imamula
 * Kevin Lang 
+* Kitson Kelly 
 * Klaus Meinhardt 
 * Kyle Kelley
 * Kārlis Gaņģis
 * Lorant Pinter
 * Lucien Greathouse
 * Lukas Elmer 
+* Magnus Hiie 
 * Manish Giri
 * Marin Marinov
 * Marius Schulz 
 * Martin Vseticka
 * Masahiro Wakame
+* Matt Bierner 
 * Matt McCutchen
 * Mattias Buelens
 * Mattias Buelens 
 * Max Deepfield
 * Micah Zoltu
 * Michael 
 * Michael Bromley
+* Mike Busyrev 
+* Mine Starks 
 * Mohamed Hegazy
 * Myles Megyesi 
+* Natalie Coley
 * Nathan Shively-Sanders
 * Nathan Yee
 * Nicolas Henry
@@ -167,6 +186,7 @@ TypeScript is authored by:
 * Punya Biswal
 * Rado Kirov
 * Raj Dosanjh
+* Richard Karmazín 
 * Richard Knoll
 * Richard Sentino
 * Robert Coie
@@ -178,13 +198,15 @@ TypeScript is authored by:
 * Ryohei Ikegami
 * Sam El-Husseini 
 * Sarangan Rajamanickam
+* Sergey Rubanov
 * Sergey Shandar 
 * Sheetal Nandi
 * Shengping Zhong
 * Shyyko Serhiy
 * Simon Hürlimann
 * Slawomir Sadziak 
 * Solal Pirelli
+* Soo Jae Hwang 
 * Stan Thomas
 * Stanislav Sysoev
 * Steve Lucco
@@ -204,6 +226,7 @@ TypeScript is authored by:
 * Tomas Grubliauskas
 * Torben Fitschen 
 * TruongSinh Tran-Nguyen
+* Vadi Taslim 
 * Vidar Tonaas Fauske
 * Viktor Zozulyak
 * Vilic Vane