Add Wall of Browser Bugs entry for #14868

Closes #14868
Merge pull request #14920 from twbs/safari-print-font-size

Add Wall of Browser Bugs entry for #14868
Add Wall of Browser Bugs entry for #14708

Closes #14708
Merge pull request #14922 from twbs/ios-cursor-scroll

Add Wall of Browser Bugs entry for #14708
Use RegExp for button plugin's focus shim

Fixes #14923.
Merge pull request #14925 from twbs/button-focus-use-regexp

Use RegExp for button plugin's focus shim
grunt
Examples: Make use of the `footer` tag instead of a `div`.