Ensure disambiguator is registered and properly type return

This was throwing off the typechecker.

src/smgdc/validate.py

@@ -17,6 +17,7 @@ import angr
 import msgspec
 
 from . import vtable as vt_helpers
+from .angr.vtable_disamb import VtableDisambiguator
 from .types import ByteSignature, Code, IntLiteral
 
 KEY_AS_IS = string.Template("${name}")
@@ -86,7 +87,7 @@ class LinuxBinary(BaseBinary):
         super().__init__(path, cache_path)
 
     @functools.cached_property
-    def vtable_disambiguator(self):
+    def vtable_disambiguator(self) -> VtableDisambiguator:
         return self.angr.analyses.VtableDisambiguator()