Completion should show results in namespaces

[digama0]

import Lean

#check elabTermEnsuringType
                         --^ textDocument/completion

returns no result, even though the document symbols (ctrl-T) request does reveal Lean.Elab.Term.elabTermEnsuringType and Lean.Elab.Tactic.elabTermEnsuringType. This is a regression compared to lean 3 and it's quite painful to not be able to complete things in other namespaces.