[lint] fix warnings (#349)

Author: apalala

Diff for: tatsu/ast.py

@@ -7,7 +7,7 @@
 from .util import asjson, is_list
 
 
-class AST(dict):
+class AST(dict):  # noqa: FURB189
     _frozen = False
 
     def __init__(self, *args, **kwargs):

Diff for: tatsu/contexts.py

@@ -101,7 +101,7 @@ def isname(impl):
     return impl
 
 
-class closure(list):
+class closure(list):  # noqa: FURB189
     def __hash__(self):
         return hash(tuple(self))
 

Diff for: tatsu/grammars.py

@@ -22,7 +22,7 @@
 PRAGMA_RE = r'^\s*#include.*$'
 
 
-class _ref(str):
+class _ref(str):  # noqa: FURB189
     def __repr__(self):
         return f'<{self}>'
 

Diff for: tatsu/infos.py

@@ -12,7 +12,7 @@
 from .util.unicode_characters import C_DERIVE
 
 
-class UndefinedStr(str):
+class UndefinedStr(str):  # noqa: FURB189
     pass