This is an extension clangd provides in LSP layer and to embedders of
ClangdServer. Currently there are no users of WantDiagnostics::Yes apart from
our tests, as from a practical point of view it is quite similar to
This patch gets rid of WantDiagnostics::Yes to get rid of some logic in
TUScheduler that handles it.
Tests are updated using the facts that an update is executed if:
- there's a read following it, or
- it is the last update in the request queue.