Fix SLOT000 (subclasses of str should define `__slots__`)

pyproject.toml

@@ -275,7 +275,6 @@ ignore = [
     "SIM117", # use single 'with' statement
     "SIM118", # use key in dict not key in dict.keys()
     # flake8-slots
-    "SLOT000",  # Subclasses of str should define __slots__
     "SLOT002",  # Subclasses of collections.namedtuple() should define __slots__
     # flake8-self
     "SLF001",  # private member accessed

sphinx/testing/path.py

@@ -34,6 +34,8 @@ class path(str):
     Represents a path which behaves like a string.
     """
 
+    __slots__ = ()
+
     @property
     def parent(self) -> path:
         """