Fix typo in docs
Merge pull request #7495 from philfreo/3.0.0-wip

Fix typo in docs
Update docs.html

Added heads up regarding lone icons providing accessibility issues for screen readers.
fixes #7497: use var for jumbotron border radius
Merge pull request #7500 from JamieKnight/patch-3

Update docs to add warning about accessibility implications of using icons without any text
Merge branch '3.0.0-wip' of github.com:twitter/bootstrap into 3.0.0-wip