Allow pressing | to surround closure arguments in VSCode

[syvb]

This makes pressing | while some text is selected surround that text with pipes. This is useful when writing closures.

In this demo, I press | to easily surround some text (predicate) with pipe characters to create a closure. Before, this would have replaced predicate with just |.

(I am getting failures when I do cargo test even on master locally (due to #8585 I think), but GH Actions is fine with this)

[matklad]

Hm, I guess I am OK with it, but this is papering over a gaping hole in our UX. I think we should:

• forcefully trigger completion when the cursor is in the position of an argument of a closure typer
• suggest |param1, param2| $0 as a completion variant

[matklad]

Alternatively, we can show two completion variants for filter:

filter(...)
filter(|x| ...)

[flodiebold]

IMO completing |x| $0 when you type | would be enough? Making | surround wouldn't actually help with that.

(The actual completion should depend on the expected closure type, of course.)

(We could/should also complete the corresponding move |x| $0...)

[matklad]

bors r+

[bors]

Build succeeded:

• Rust (macos-latest)
• Rust (ubuntu-latest)
• Rust (windows-latest)
• TypeScript (ubuntu-latest)
• TypeScript (windows-latest)

[lnicola]

changelog feat (first contribution) allow pressing | to surround closure arguments in VS Code