Keybind C-f on the main page

[arrdem]

Since the front cheatsheet as a navigation mechanism should have been largely replaced by the new search bar which searches the whole site for content including reader notation there really isn't a reason for a user to use the browser's C-f textual search.

While the search bar is already autoselected, maybe it makes sense for C-f to be captured to select the search bar.

[arrdem]

With respect to #231 this is a terrible idea. Closing as such.