refactor: more type hints

src/awkward/types/type.py

@@ -45,19 +45,19 @@ def show(self, stream=sys.stdout):
 
     _str_parameters_exclude = ("__categorical__",)
 
-    def _str_categorical_begin(self):
+    def _str_categorical_begin(self) -> str:
         if self.parameter("__categorical__") is not None:
             return "categorical[type="
         else:
             return ""
 
-    def _str_categorical_end(self):
+    def _str_categorical_end(self) -> str:
         if self.parameter("__categorical__") is not None:
             return "]"
         else:
             return ""
 
-    def _str_parameters(self):
+    def _str_parameters(self) -> str:
         out = []
         if self._parameters is not None:
             for k, v in self._parameters.items():
@@ -72,7 +72,7 @@ def _str_parameters(self):
         else:
             return "parameters={" + ", ".join(out) + "}"
 
-    def _repr_args(self):
+    def _repr_args(self) -> list[str]:
         out = []
 
         if self._parameters is not None and len(self._parameters) > 0: