[4.2.x] Corrected code-block directives in docs.

Backport of 024954aad4c422a091b7afab42fff1a9d7478fce from main

docs/ref/files/file.txt

@@ -135,7 +135,7 @@ below) will also have a couple of extra methods:
     Saves a new file with the file name and contents provided. This will not
     replace the existing file, but will create a new file and update the object
     to point to it. If ``save`` is ``True``, the model's ``save()`` method will
-    be called once the file is saved. That is, these two lines::
+    be called once the file is saved. That is, these two lines:
 
     .. code-block:: pycon
 

docs/ref/templates/builtins.txt

@@ -1116,7 +1116,7 @@ Example usage:
         {% resetcycle %}
     {% endfor %}
 
-This example would return this HTML::
+This example would return this HTML:
 
 .. code-block:: html