Allow user remapping of "repeat last insert"

[eugenesvk]

As far as I understand, there is no "repeat last command" command, you must use the default . keybind

I'd like to move this command to a different key, so I'd need a repeat_last_command command I could use

[archseer]

For historical reasons this is currently a builtin https://github.com/helix-editor/helix/blob/a2fad4fcb0c4a0547a86cb18820f2c8612991a1d/helix-term/src/ui/editor.rs#L730-L738

but since macros don't have this limitation and also do a similar thing I think it should be possible to refactor this into a command now 👍🏻

[rcorre]

A side-effect of this is that you can't map anything else to .

[stindrago]

This issue is painful 😩. I am coming from a different editor and I am accustomed to using . for a different thing.