header edit links on mobile

[gregwebs]

In the HTML view mode we automatically link document headers to edit mode at the heading. On mobile a user could easily accidentally end up clicking the link. Lets try the new version out and see what users report.

There are 2 approaches to improving the links

• do some extra checks of touch events
• disable on mobile (we now use isTouchScreen from utils)

Another approach would be to put an edit icon next to the header. Downsides to this approach

• There could be some tricky formatting issues for some docs
• it provides a smaller area to click
• it is still possible to accidentally click the edit icon (on mobile)