{"textDocument": {"version": 2, "uri": "file://editCompletion.lean"},
 "contentChanges":
 [{"text": ".",
   "range":
   {"start": {"line": 3, "character": 21},
    "end": {"line": 3, "character": 22}}}]}
{"textDocument": {"uri": "file://editCompletion.lean"},
 "position": {"line": 3, "character": 22}}
{"items": [{"label": "foo", "detail": "Foo → Nat"}], "isIncomplete": true}