Button dropdown example markup missing role="menu"

Created by: madjake

Problem: Button drop down example markup missing role="menu" which causes arrow key navigation to not work

URL: http://getbootstrap.com/components/#input-groups-buttons-dropdowns

Description: The example markup in the documentation for button drop downs is missing the role="menu" attribute on the UL's. This causes arrow key navigation of the drop down to not work.

The actual examples include role="menu" so they appear to work fine but a new user or somebody evaluating the feature might copy & paste and not realize why arrow key navigation does not work. (See real instance of this happening here: http://stackoverflow.com/questions/23919755/dropdown-toggle-not-responding-to-key-commands/23919863#23919863)