DOC: Remove old information in docstring.

_pcolormesh_patched is no longer used as a workaround for anything.

Closes #992.

lib/cartopy/mpl/geoaxes.py

@@ -1448,12 +1448,11 @@ def pcolormesh(self, *args, **kwargs):
 
     def _pcolormesh_patched(self, *args, **kwargs):
         """
-        A temporary, modified duplicate of
-        :func:`~matplotlib.pyplot.pcolormesh'.
+        A modified duplicate of :func:`~matplotlib.pyplot.pcolormesh'.
 
-        This function contains a workaround for a Matplotlib issue
-        and will be removed once the issue has been resolved.
-        https://github.com/matplotlib/matplotlib/pull/1314
+        This function contains patches for Cartopy-specific behaviour, such as
+        using the transform for limit checks, applying longitude wrapping, etc.
+        See PATCH comments below.
 
         """
         import warnings