[12.x] add migrate:redo command (alias of migrate:refresh --step=1)

[adammatysiak]

One-line alias for migrate:refresh --step=1 that mirrors Rails’ db:migrate:redo, saves keystrokes when iterating on a single migration.

New RedoCommand extending RefreshCommand, registered in MigrationServiceProvider.

3 console tests added in tests\Database\DatabaseMigrationRedoCommandTest.php mirroring the Refresh command.

Non-breaking backwards compatibility.

The alternative is using the existing migrate:refresh --step=1; this alias is for convenience.

The docs would need to be updated under src/docs/12.x/migrations.md:

### Redo

`php artisan migrate:redo`

Rolls back the most recent batch and immediately re-runs it.  
It is equivalent to `migrate:refresh --step=1`.

[taylorotwell]

You could probably just bash alias migrate:refresh --step=1