fix: use async for moving cursor with dot repeat

[saghen]

I don't love this solution in general, so please feel free to suggest other ideas!

We use <C-g>U<Left> to move the cursor backwards after accepting with auto-brackets (move_cursor_in_dot_repeat). However, because we use feedkeys, the input is queued for processing, but doesn't get processed until after vim.schedule. This means we don't have an easy way to wait for it to finish processing and the downstream show_if_on_trigger_character() will see the cursor at test()| instead of at test(|).

I've setup an autocmd that listens for a CursorMoved/CursorMovedI event (need CursorMovedC too, but that's nvim 0.11+. need to test terminal too) and resolves the move_cursor_in_dot_repeat task when the autocmd fires. Notably, this makes the default_implementation passed to source:execute Task rather than void, so sources would need to be updated to support this.

Closes #1685

[canova]

Thanks for the PR!

Notably, this makes the default_implementation passed to source:execute Task rather than void, so sources would need to be updated to support this.

This makes sense, but we don't need to do anything for LSP sources since this PR updates it already, right?

I tried this PR locally with my STR in #1685, and I still can't get the signature show up on the JS (with ts_ls) files. But I'm not entirely sure if there is something else needed.