Hardcode case where last token is 'AS'

Fixes failing tests. In earlier versions of sqlparse this dangling AS was grouped with the previous
identifier so this case was handled implicitly

pgcli/packages/sqlcompletion.py

@@ -358,7 +358,9 @@ def suggest_based_on_last_token(token, stmt):
             return (Column(table_refs=tables, local_tables=stmt.local_tables),
                     Function(schema=None),
                     Keyword(),)
-
+    elif token_v == 'as':
+        # Don't suggest anything for aliases
+        return ()
     elif (token_v.endswith('join') and token.is_keyword) or (token_v in
             ('copy', 'from', 'update', 'into', 'describe', 'truncate')):