Fuzzy search in help menu

**Is your feature request related to a problem? Please describe.**
In some views there are quite a few options when bringing up the help menu. I mostly use help for actions I don't use very often and therefore don't know or dare not guess what the key binding is.

**Describe the solution you'd like**
A search field in the top of the help popup. Arrow keys still move up and down the list and enter selects, but other keys send input to the search field which then sorts results via fuzzy finder (fzf).

**Describe alternatives you've considered**
An alternative is looking through the list, which is cumbersome.

**Additional context**
Nope. But keep up the good work. :)