Add option to dump currently loaded keymap config

[noyez]

As a method to add a self-documenting feature, believe it would helpful to add an option to dump the current keymap configuration (or maybe the whole configuration). This would serve 2 purposes

1. give a user a starting point for a valid and properly formatted configuration with all options.
2. list all keymap configuration modes and options.

I use a similar option w/ zellij, namely zellij setup --dump-config will dump the whole configuration to stdout. This allows me to see all possible keymappings in a properly configured format.

[noyez]

Excuse me, the official doc lacks what config?

For example, i wanted to remap C-o in windowed mode as i kept on hitting it by mistake. I looked over the docs to figure out how to do that, but i couldn't find it in the docs. If i am missing this, then please let me know. The goal if this issue is to offer a complete dump of the config so the user explore every config option.

As an example my journey to remap C-o in window mode looked like the following,

i first tried

[keys.window]
C-o = "no_op"

But that lead to Invalid mode 'window',

then i tired

[keys.windowed]
C-o = "no_op"

But that lead to Invalid mode 'windowed',

then i tried something like

[keys.normal]
C-o = "no_op"

That at least parsed, but didn't achieve my goal.

After searching around i finally figured out the proper way to remap a key in windowed mode.

[keys.normal.C-w]
o = "rotate_view"
C-o = "no_op"

I do not believe this is mentioned in the docs, and i don't think it needs to be mentioned since it is a niche keymap. However I believe if there was a way to dump the whole config to stdout or a file, a user would be able to see valid syntax for various modes and other options. I see it as a discoverability feature.

[kirawi]

1. give a user a starting point for a valid and properly formatted configuration with all options.

This was mentioned in #655. It sounds like an easy addition, but I'm not sure how the maintainers feel about it.