LSP 3.16: Use workspace/willRenameFiles and/or worskspace/didRenameFiles to automatically rename modules

[kjeremy]

Once #6779 is in we will gain the ability to use these (and their create/delete variants) to detect file operations in supporting clients. We should use these to do things like: client has renamed foo.rs to bar.rs so update the foo mod to be bar.

[kjeremy]

See: microsoft/language-server-protocol#984