element_list: labels -> label for consistency

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@64092 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/python/pygrass/gis/__init__.py

@@ -304,7 +304,7 @@ class Mapset(object):
         """Return a list of grass types like:
 
             * 'group',
-            * 'labels',
+            * 'label',
             * 'raster',
             * 'raster_3d',
             * 'region',