Add Wall of Browser Bugs entry for #14972
Merge pull request #14985 from twbs/14972-wall

Add Wall of Browser Bugs entry for #14972
Add event.relatedTarget + `data-*` example to Modal docs

Fixes #14245
Merge pull request #14989 from twbs/modal-relatedTarget-data-example

Add event.relatedTarget + `data-*` example to Modal docs
Remove duplicate code from Customizer/Gruntfile by sharing it