Fixes #31244.
Fixes #25691.

As I said in #59339, our existing behavior, implemented based on vscode's behavior, is that whenever isNewIdentifierLocation is true, we disable all commit characters, otherwise the commit characters are ., ,, ;.

However, there have been issues opened over time that this approach is too conservative.
This PR enables some of the usual commit characters in some places where isNewIdentifierLocation is true and that previously we'd enable no commit characters.

Mainly, this PR enables all the three commit characters in every position where an expression is expected. In some of those positions, where we are inside an open parenthesis, the user could be typing a parameter list for an arrow expression, so we disable , as a commit character.

I considered adding space as a commit character too, but we would have to disable it pretty much everywhere where isNewIdentifierLocation is true because space could validly follow a new identifier in all of those places, so I figured users wouldn't be able to use it reliably as a commit character and it didn't seem like a good idea.

This PR should be testable in vscode insiders once it picks up microsoft/vscode#223541.