{"textDocument": {"uri": "file:///editCompletion.lean"},
 "position": {"line": 3, "character": 22}}
{"items":
 [{"label": "foo",
   "kind": 5,
   "data": ["«external:file:///editCompletion.lean»", 3, 22, 1, "cFoo.foo"]}],
 "isIncomplete": false}