Fix issues detected by pytype

Author: oprypin

mkdocstrings/handlers/crystal/crystal_html.py

@@ -1,7 +1,7 @@
 import collections
 import html.parser
 import io
-from typing import Callable, Iterable, List, Sequence, Tuple
+from typing import Callable, Iterable, List, Optional, Sequence, Tuple
 
 from markupsafe import Markup, escape
 

mkdocstrings/handlers/crystal/items.py

@@ -293,11 +293,7 @@ class DocConstant(DocItem):
     _TEMPLATE = "constant.html"
 
     @property
-    def full_name(self):
-        return (self.parent.full_name + "::" if self.parent else "") + self.name
-
-    @property
-    def abs_id(self):
+    def abs_id(self) -> str:
         return (
             self.parent.abs_id + "::" if self.parent and self.parent.parent else ""
         ) + self.rel_id