Add: Filter by mode for command_pallete (Spc-?)

[darshanCommits]

Now you can filter by mode while searching for correct keybind.

First time contribution, and not a very experienced dev (more so in rust)
Review outside of core maintainers appreciated.

[david-crespo]

Does that mean there is now an entry in the list for all three modes for every command? It will feel weird if you search by command name and get three rows every time.

One way to avoid that would be to a bindings column for each mode. That way the three modes are all in one row. But that could get weird in other ways, and would take up more horizontal space.

[darshanCommits]

Good catch.
How should this be handled?

How about, unless %m provided, only result in the current mode?