Refs #20910 -- Replaced snippet directive with code-block.

docs/topics/auth/passwords.txt

@@ -251,8 +251,8 @@ modify the pattern to work with any algorithm or with a custom user model.
 
 First, we'll add the custom hasher:
 
-.. snippet::
-    :filename: accounts/hashers.py
+.. code-block:: python
+    :caption: accounts/hashers.py
 
     from django.contrib.auth.hashers import (
         PBKDF2PasswordHasher, SHA1PasswordHasher,
@@ -271,8 +271,8 @@ First, we'll add the custom hasher:
 
 The data migration might look something like:
 
-.. snippet::
-    :filename: accounts/migrations/0002_migrate_sha1_passwords.py
+.. code-block:: python
+    :caption: accounts/migrations/0002_migrate_sha1_passwords.py
 
     from django.db import migrations
 
@@ -306,8 +306,8 @@ several thousand users, depending on the speed of your hardware.
 
 Finally, we'll add a :setting:`PASSWORD_HASHERS` setting:
 
-.. snippet::
-    :filename: mysite/settings.py
+.. code-block:: python
+    :caption: mysite/settings.py
 
     PASSWORD_HASHERS = [
         'django.contrib.auth.hashers.PBKDF2PasswordHasher',