Remove unnecessary super calls

I previously misunderstood the on_visit method.
We don't need to call super.on_visit, simply
returning True/False is enough.

Author: Otto-AA

mutmut/file_mutation.py

@@ -84,7 +84,7 @@ def __init__(self, provider: "OuterFunctionProvider", top_level_node: cst.CSTNod
 
     def on_visit(self, node: cst.CSTNode):
         self.provider.set_metadata(node, self.top_level_node)
-        return super().on_visit(node)
+        return True
 
 
 class MutationVisitor(cst.CSTVisitor):
@@ -108,7 +108,7 @@ def on_visit(self, node):
             self._create_mutations(node)
 
         # continue to mutate children
-        return super().on_visit(node)
+        return True
 
     def _create_mutations(self, node: cst.CSTNode):
         for t, operator in self._operators: