Update docs with new skip marker

doc/en/skipping.rst

@@ -31,7 +31,15 @@ Marking a test function to be skipped
 
 .. versionadded:: 2.0, 2.4
 
-Here is an example of marking a test function to be skipped
+The simplest way to skip a function is to mark it with the `skip` decorator,
+which may be passed an optional `reason`:
+
+    @pytest.mark.skip(reason="no way of currently testing this")
+    def test_the_unknown():
+        ...
+
+If you wish to skip something conditionally then you can use `skipif` instead.
+Here is an example of marking a test function to bwe skipped
 when run on a Python3.3 interpreter::
 
     import sys