Bad property name for indices description in docs

The correct name for MongoDB index definition property is weights not weight. Using "weight" will cause "Index with name ... already exists with different options"

docs/guide/text-indexes.rst

@@ -17,7 +17,7 @@ Use the *$* prefix to set a text index, Look the declaration::
       meta = {'indexes': [
           {'fields': ['$title', "$content"],
            'default_language': 'english',
-           'weight': {'title': 10, 'content': 2}
+           'weights': {'title': 10, 'content': 2}
           }
       ]}