Correct ApiQueryLanguageStats example

Change-Id: I520f99f99af3c38644f4aae187a115f40464ac98
Use constant group name in examples

See I46ac1a73 for more information.

Change-Id: I40f61532a1e23a72b51f97febb61cc700080a69b
Merge changes I40f61532,I520f99f9

* changes:
  Use constant group name in examples
  Correct ApiQueryLanguageStats example