PY-16412 Fixed handling of callable types in the intention

by adding an alternative implementation of TypeVisitor that strives
to render a type in PEP 484 compatible format.

python/testSrc/com/jetbrains/python/intentions/PyAnnotateVariableTypeIntentionTest.java

@@ -223,6 +223,10 @@ public class PyAnnotateVariableTypeIntentionTest extends PyIntentionTestCase {
     doAnnotationTest();
   }
 
+  public void testAnnotationNotPossibleForStructuralTypeInCallable() {
+    doAnnotationTest();
+  }
+
   public void testAnnotationCallableType() {
     doAnnotationTest();
   }