Support "wrap with snippet"

[pokey]

The goal

VSCode has support for snippets that can take a selection. We'd like to use this to enable things such as "if state wrap air", "try state wrap air", etc

Implementation plan

Extension

We propose to add a new action. Check out simple actions like ExtractVariable as a starting point.

The action will call editor.insertSnippet.

We will keep language-specific snippets for each syntactic scope type, similar to how we do for finding containing scope; see eg https://github.com/pokey/cursorless-vscode/blob/fdebfe93c7871a3e3bf832532f51cf64b8f3c3a8/src/languages/python.ts#L46-L68 Note that the snippet will leverage TM_SELECTED_TEXT to refer to where the target that is wrapped will go. We can add tabstops for things like if statement guard, catch block, etc

The action will take an extra arg which is the scopetype to wrap with, eg ifStatement. See Wrap for example of taking extra args

Talon

Add a new capture like "wrap" that accepts a scope type. Something like "<scopeType> wrap <target>"