Show infobox to hint textobjects with mi and ma

[EpocSquadron]

We should probably add to the status area as well, but this is a significant improvement in discoverability for textobject surround selection.

[EpocSquadron]

I cleaned up a bug that was swallowing input if you cancelled with escape while in the middle of a mi or ma. I also improved the help text a bit.

[EpocSquadron]

Also added the pending keys below the status bar. This should help in cases where people turn off the info box in their config. I can remove that part as it's a bit hackier than the rest. Let me know and i'll force push to remove it and maybe open a separate pr after this one is merged.

[sudormrfbin]

Ideally every textobject would be split into it's on bindable function so that #1595 gets completely resolved (and we would not have to manually show the infobox either). But it's currently blocked on not being able to execute a fallback function if none of the keys match, which would be required to make the surround objects like mi( work. I think it's good enough as a temporary solution (at the risk of it slipping into being the permanent solution :P).

Showing pending keys should also be ideally reworked to automatically work based on if there's an on_next_key callback registered. This has the benefit of working everywhere like f, mi, etc.

[pickfire]

But it's currently blocked on not being able to execute a fallback function if none of the keys match, which would be required to make the surround objects like mi( work.

I think we should just add a function for each of these rather than having a fallback. An exhaustive list should work fine like kakoune, then we don't have to handle wildcard.

[sudormrfbin]

Defining a function for every single surround pair ((, [, {, ', ", <, `, and these are only the opening pairs) would be wasteful, and it would definitely clutter up the infobox. Besides it would be useful to be able to have any character act as a surround delimiter (for example using mi~ to select inside strikethrough text in markdown).

[EpocSquadron]

I agree with @sudormrfbin on this. Another case where it is useful is if you have an @ delimited regex in a web context, or some markup using a pair of delimiters like {% %}.

I've been mulling over how to refactor to address the other feedback. I'm probably a couple days away from being able to fully address.

[pickfire]

That is good too but not every places uses the same method, I have seen some text that uses ` and ' for opening and closing quote and we have no way around that. Yeah, I guess we could have a fallback, IIRC I did fallback for the older paragraph pull request I sent but I scraped that changes.

[EpocSquadron]

Ideally every textobject would be split into it's on bindable function so that #1595 gets completely resolved (and we would not have to manually show the infobox either). But it's currently blocked on not being able to execute a fallback function if none of the keys match, which would be required to make the surround objects like mi( work. I think it's good enough as a temporary solution (at the risk of it slipping into being the permanent solution :P).

Showing pending keys should also be ideally reworked to automatically work based on if there's an on_next_key callback registered. This has the benefit of working everywhere like f, mi, etc.

I don't have the bandwidth to do this level of refactor yet. Hoping we can get this in as a first pass and revisit later.