PY-16412 Proper use of a smart pointer in case of malformed annotations

Namely, it was mistakenly dereferenced before the document was
committed after modifications.

Callable types are still not rendered properly in PEP 484 compatible
format, but at least they don't lead to PIEAE anymore.

python/src/com/jetbrains/python/codeInsight/intentions/PyTypeHintGenerationUtil.java

@@ -128,10 +128,10 @@ public class PyTypeHintGenerationUtil {
       final PyAssignmentStatement assignment = (PyAssignmentStatement)target.getParent();
       final SmartPsiElementPointer<PyAssignmentStatement> pointer = manager.createSmartPsiElementPointer(assignment);
       addOrUpdateAnnotatedStatement = () -> {
-        return PyUtil.updateDocumentUnblockedAndCommitted(target, document -> {
+        PyUtil.updateDocumentUnblockedAndCommitted(target, document -> {
           document.insertString(target.getTextRange().getEndOffset(), ": " + info.getAnnotationText());
-          return pointer.getElement();
         });
+        return pointer.getElement();
       };
     }
     else {

python/testData/intentions/PyAnnotateVariableTypeIntentionTest/annotationCallableType.py

@@ -0,0 +1,5 @@
+def func(x):
+    pass
+
+
+va<caret>r = func

python/testData/intentions/PyAnnotateVariableTypeIntentionTest/annotationCallableType_after.py

@@ -0,0 +1,8 @@
+from typing import Any, Callable
+
+
+def func(x):
+    pass
+
+
+var: Callable[[Any], None] = func

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

@@ -223,6 +223,10 @@ public class PyAnnotateVariableTypeIntentionTest extends PyIntentionTestCase {
     doAnnotationTest();
   }
 
+  public void testAnnotationCallableType() {
+    doAnnotationTest();
+  }
+
   private void doAnnotationTest() {
     doTest(LanguageLevel.PYTHON36);
   }