DOC make it more explicit selector_to_text is parsel-specific

Author: kmike

html_text/html_text.py

@@ -138,7 +138,7 @@ def traverse_text_fragments(tree, context, handle_tail=True):
 
 
 def selector_to_text(sel, guess_punct_space=True, guess_layout=True):
-    """ Convert a cleaned selector to text.
+    """ Convert a cleaned parsel.Selector to text.
     See html_text.extract_text docstring for description of the approach
     and options.
     """