Support numeric ranges for insert

[pokey]

If you have 5 cursors, you could say "insert range 1 to 5 pre this". For example, if you have a cursor at the beginning of each of these lines:

foo
bar
baz
bongo

Then saying "insert range 1 to 4 pre this", you'd get the following:

1foo
2bar
3baz
4bongo

Probably talon would just send a list to vscode, which would then zip it with the targets as normal. So the range would just operate like "square" etc as described in #15

Could also have a simplified version which is just "insert count pre this", or "insert count from two pre this", and it would count as necessary

Could also do alphabet ranges