[5.0.x] Improved wording in auth.models.User field docs.

Co-authored-by: Lily Foote <code@lilyf.org>

Backport of 79099a7ba454581ab521fcb4ea61fc6ed3dccf26 from main

docs/ref/contrib/auth.txt

@@ -67,14 +67,14 @@ Fields
 
     .. attribute:: is_staff
 
-        Boolean. Designates whether this user can access the admin site.
+        Boolean. Allows this user to access the admin site.
 
     .. attribute:: is_active
 
-        Boolean. Designates whether this user account should be considered
-        active. We recommend that you set this flag to ``False`` instead of
-        deleting accounts; that way, if your applications have any foreign keys
-        to users, the foreign keys won't break.
+        Boolean. Marks this user account as active. We recommend that you set
+        this flag to ``False`` instead of deleting accounts. That way, if your
+        applications have any foreign keys to users, the foreign keys won't
+        break.
 
         This doesn't necessarily control whether or not the user can log in.
         Authentication backends aren't required to check for the ``is_active``
@@ -94,8 +94,8 @@ Fields
 
     .. attribute:: is_superuser
 
-        Boolean. Designates that this user has all permissions without
-        explicitly assigning them.
+        Boolean. Treats this user as having all permissions without assigning
+        any permission to it in particular.
 
     .. attribute:: last_login
 
@@ -103,8 +103,7 @@ Fields
 
     .. attribute:: date_joined
 
-        A datetime designating when the account was created. Is set to the
-        current date/time by default when the account is created.
+        The date/time when the account was created.
 
 Attributes
 ----------