extract method: suggest non-void return type if final field is assigned inside (IDEA-93737)

java/java-tests/testData/refactoring/extractMethod/ReassignFinalFieldInside.java

@@ -0,0 +1,10 @@
+class X {
+  private final int i;
+
+  public X() {
+    <selection>
+       i = 0;
+       System.out.println(i);
+    </selection>
+  }
+}

java/java-tests/testData/refactoring/extractMethod/ReassignFinalFieldInside_after.java

@@ -0,0 +1,16 @@
+class X {
+  private final int i;
+
+  public X() {
+
+      i = newMethod();
+    
+  }
+
+    private int newMethod() {
+        int i;
+        i = 0;
+        System.out.println(i);
+        return i;
+    }
+}