core.py: document grass.separator() (updates https://trac.osgeo.org/grass/changeset/60622)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@60629 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/python/script/core.py

@@ -676,6 +676,13 @@ def parser():
 
 
 def separator(sep):
+    """!Returns separator from G_OPT_F_SEP appropriately converted
+    to character.
+
+    @param separator character or separator keyword
+
+    @return separator character
+    """
     if sep == "pipe":
         return "|"
     elif sep == "comma":