Add a how do I box

[kjlubick]

E.g. I'm in google docs and I forget how to add a comment, I hit the coach button or hit a keyboard shortcut, a box pops up, I type free text what I'm looking for (e.g. "comment") and the relevant keyboard shortcut pops up, or the menu is highlighted.

Popping up the keyboard shortcut shouldn't be hard, but the menu highlighting may be difficult and require lots of patches.