Inlay hints should accept a list of files, not individual files

[DanielRosenwasser]

Inlay hints can be affected by edits in other files. That means you can end up in situations where 2 files can be edited side-by-side where one ends up with stale inlay hints.

To spare editors from making multiple requests, we should consider accepting a list of files instead of a single file as an argument.

Tracking on VS Code's side: microsoft/vscode#130430

[DanielRosenwasser]

If we do this, we'll have a mismatch in client/server for a bit. We can have the public API accept a list, and temporarily support individual files.

[Kingwl]

Sorry my bad. Would we just add a new command?

[DanielRosenwasser]

We discussed it in our editor sync; it seems like there's not a huge win from changing TSServer - but at the least, we think editors should try to request on visible files (in an optimal order). We'll revisit if this comes up again.