Editor itself is able to invalidate hints after edits, and /refresh was
sent after editor reports changes to the language server.
This forces the editor to either query & invalidate the hints twice
after every edit, or wait for /refresh to come before querying the
hints.
Both options are rather useless, so instead, send a request on server
startup only: client editors do not know when the server actually starts
up, this will help to query the initial hints after editor was open and
the server was still starting up.