[1.8.x] Refs #17785 -- Made docstring for sqlite3's get_relations() consistent with other backends.

Backport of 4b9d063da0 from master

django/db/backends/sqlite3/introspection.py

@@ -88,10 +88,9 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
 
     def get_relations(self, cursor, table_name):
         """
-        Returns a dictionary of {field_index: (field_index_other_table, other_table)}
-        representing all relationships to the given table. Indexes are 0-based.
+        Return a dictionary of {field_name: (field_name_other_table, other_table)}
+        representing all relationships to the given table.
         """
-
         # Dictionary of relations to return
         relations = {}