[4.0.x] Fixed docs build with sphinxcontrib-spelling 7.5.0+.

sphinxcontrib-spelling 7.5.0+ includes captions of figures in the set
of nodes for which the text is checked.

Backport of ac90529cc5 from main.

docs/ref/contrib/admin/index.txt

@@ -3115,7 +3115,7 @@ it instead of with the default site. Finally, update :file:`myproject/urls.py`
 to reference your :class:`AdminSite` subclass.
 
 .. code-block:: python
-    :caption: myapp/admin.py
+    :caption: ``myapp/admin.py``
 
     from django.contrib import admin
 
@@ -3129,7 +3129,7 @@ to reference your :class:`AdminSite` subclass.
 
 
 .. code-block:: python
-    :caption: myproject/urls.py
+    :caption: ``myproject/urls.py``
 
     from django.urls import path
 
@@ -3156,7 +3156,7 @@ to the dotted import path of either a ``AdminSite`` subclass or a callable that
 returns a site instance.
 
 .. code-block:: python
-    :caption: myproject/admin.py
+    :caption: ``myproject/admin.py``
 
     from django.contrib import admin
 
@@ -3164,7 +3164,7 @@ returns a site instance.
         ...
 
 .. code-block:: python
-    :caption: myproject/apps.py
+    :caption: ``myproject/apps.py``
 
     from django.contrib.admin.apps import AdminConfig
 
@@ -3172,7 +3172,7 @@ returns a site instance.
         default_site = 'myproject.admin.MyAdminSite'
 
 .. code-block:: python
-    :caption: myproject/settings.py
+    :caption: ``myproject/settings.py``
 
     INSTALLED_APPS = [
         ...

docs/ref/contrib/admin/javascript.txt

@@ -32,7 +32,7 @@ In your custom ``change_form.html`` template, extend the
     {% endblock %}
 
 .. code-block:: javascript
-    :caption: app/static/app/formset_handlers.js
+    :caption: ``app/static/app/formset_handlers.js``
 
     (function($) {
         $(document).on('formset:added', function(event, $row, formsetName) {
@@ -70,7 +70,7 @@ listen to the event triggered from there. For example:
     {% endblock %}
 
 .. code-block:: javascript
-    :caption: app/static/app/unregistered_handlers.js
+    :caption: ``app/static/app/unregistered_handlers.js``
 
     django.jQuery(document).on('formset:added', function(event, $row, formsetName) {
         // Row added