Make consistent WRT "--dont-report-useless-tests"

See #15: "--report-useless-tests" (old) vs. "--dont-report-useless-tests" (new)

Author: reinholdfuereder

src/textui.rst

@@ -340,9 +340,9 @@ the following code:
 
     Only search for test files with specified suffix(es).
 
-``--report-useless-tests``
+``--dont-report-useless-tests``
 
-    Be strict about tests that do not test anything. See :ref:`risky-tests` for details.
+    Do not report tests that do not test anything. See :ref:`risky-tests` for details.
 
 ``--strict-coverage``