Fix edit remove snippets

[Kuuuube]

Fixes #52 and somewhat #53

The result of autocomplete_snippet is the id and title, not the id. So using get_snippet instead of get_snippet_lazy is possible here. Edit and remove snippet are also slash command only so this doesnt create an issue for trying to use it as a prefix command.

If there's a snippet with both the same id and title, this wont help but that isnt supposed to be possible.

Edit snippet now actually edits the snippet instead of creating a new snippet.