bug #4603 Replace form_enctype(form) with form_start(form). (xelaris)

This PR was merged into the 2.3 branch.

Discussion
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Replace form_enctype(form) with form_start(form).

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | >=2.3
| Fixed tickets |

Since form_enctype(form) is deprecated since 2.3 form_start(form) should be used.

Commits
-------

21d69eb Replace form_enctype(form) with form_start(form).

Author: weaverryan

best_practices/forms.rst

@@ -139,12 +139,12 @@ view layer:
 
 .. code-block:: html+jinja
 
-    <form method="POST" {{ form_enctype(form) }}>
+    {{ form_start(form) }}
         {{ form_widget(form) }}
 
         <input type="submit" value="Create"
                class="btn btn-default pull-right" />
-    </form>
+    {{ form_end(form) }}
 
 Rendering the Form
 ------------------