[5.0.x] Fixed incorrect blockquotes in docs/topics/forms/index.txt.

Backport of bcad5ad from main

docs/topics/forms/index.txt

@@ -781,12 +781,10 @@ Useful attributes on ``{{ field }}`` include:
         <label for="id_email">Email address:</label>
 
 ``{{ field.legend_tag }}``
-
     Similar to ``field.label_tag`` but uses a ``<legend>`` tag in place of
     ``<label>``, for widgets with multiple inputs wrapped in a ``<fieldset>``.
 
 ``{{ field.use_fieldset }}``
-
     This attribute is ``True`` if the form field's widget contains multiple
     inputs that should be semantically grouped in a ``<fieldset>`` with a
     ``<legend>`` to improve accessibility. An example use in a template: