L3MON4D3

This is similar to #797, a description for achieving this via api is in there, but I haven't considered just using undo for this. Is it possible to register a...

Ahh okay, thank you! That seems like something we could just always do before expanding a snippet.. Although `undo` won't affect internal variables (the current node), which would have to...

Slightly better: set the new undo-point in (/around?) `snip_expand`, that's the function which actually expands the snippets