Removed initial data from flush docs since it's removed; refs #24711.

.. django-admin:: flush

Removes all data from the database, re-executes any post-synchronization

handlers, and reinstalls any initial data fixtures.

Removes all data from the database and re-executes any post-synchronization

handlers. The table of which migrations have been applied is not cleared.

If you would rather start from an empty database and re-run all migrations, you

should drop and recreate the database and then run :djadmin:`migrate` instead.

The :djadminopt:`--noinput` option may be provided to suppress all user

prompts.