Delete and move/rename buffer and associated file commands

[Kim-Dewelski]

I personally find it somewhat annoying that Helix is able to create new files via the open command, but lacks the ability to delete a buffer and its associated file, or move/rename a file associated with a buffer to a different location. If I remove a file externally via something like rm, the buffer remains alive and it is very easy to accidentally create the old file from the buffer again. This is great and all in a lot of cases, but sometimes I just want to close a buffer and delete its associated file, so I believe helix would benefit from these additions.

[kirawi]

Move is supported on master via the LSP spec. We can also support deleting files (and opening files) through the LSP spec. I'm not sure how Blaz feels about having a non-LSP implementation.

[Kim-Dewelski]

What are some of the reason to not include a :delete command which just closes the buffer, and deletes the associated underlying file? Is there a technical or opinionated reason mainly? I would gladly love to make a PR if I know it would be considered.

[kirawi]

This is actually a duplicate of #4592