Rename aria-label to generate search report instead of Search Report

[bhavyarm]

Kibana version: 6.3.0 BC6

Browser version: chrome latest

Browser OS version: OS X

Original install method (e.g. download page, yum, from source, etc.): from staging

Describe the bug: Aria-label for reporting on discover should be renamed to generate search report instead of search report. So screenreaders can accurately announce that clicking that button will facilitate generation of search reports.

[stacey-gammon]

If we are being very literal, clicking on that top button won't actually generate the report, it will only open the reporting panel. So maybe it's more accurate the way it is now? The actual button has the Generate prefix...

[bhavyarm]

@aphelionz what do you think? What Stacey is saying makes sense but for me its not completely accessible. But am fine to close it if you are ok with it. Thanks!

[stacey-gammon]

Discussed and decided it's good as is