fix #13697

[skip sauce]
add missing role="menu" attrs to .dropdown-menu elements in docs+examples

Docs audit prompted by #13697.
[skip sauce]
Merge pull request #13700 from twbs/role-menu-all-the-things

add missing role="menu" attrs to .dropdown-menu elements in docs+examples
Changed broken #authors anchor to #creators
Merge pull request #13716 from rustinlee/fix-creators-anchor

Changed broken #authors anchor to #creators
Add changes from upstream