Fix intro doc typos, and update deprecated links

[gin]

• Targeted PR against correct branch (see CONTRIBUTING.md)

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

• Wrote tests

• Updated relevant documentation (docs/)

• Added entries in PENDING.md with issue #

• rereviewed Files changed in the github PR explorer

---

For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (develop@4b765b6). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             develop    #3847   +/-   ##
==========================================
  Coverage           ?   60.83%           
==========================================
  Files              ?      192           
  Lines              ?    14288           
  Branches           ?        0           
==========================================
  Hits               ?     8692           
  Misses             ?     5029           
  Partials           ?      567

[cwgoes]

ACK; thanks