Fixed #31262 -- Added support for mappings on model fields and ChoiceField's choices.

docs/topics/forms/modelforms.txt

@@ -173,11 +173,11 @@ Consider this set of models::
     from django.db import models
     from django.forms import ModelForm
 
-    TITLE_CHOICES = [
-        ("MR", "Mr."),
-        ("MRS", "Mrs."),
-        ("MS", "Ms."),
-    ]
+    TITLE_CHOICES = {
+        "MR": "Mr.",
+        "MRS": "Mrs.",
+        "MS": "Ms.",
+    }
 
 
     class Author(models.Model):