docs: improve command sample

'\' is a meta character in the shell.

Author: kenjis

user_guide_src/source/dbmgmt/migration.rst

@@ -201,9 +201,9 @@ You can use (migrate) with the following options:
 - ``-n`` - to choose namespace, otherwise (App) namespace will be used.
 - ``--all`` - to migrate all namespaces to the latest migration
 
-This example will migrate Blog namespace with any new migrations on the test database group::
+This example will migrate ``Acme\Blog`` namespace with any new migrations on the test database group::
 
-    > php spark migrate -g test -n Blog
+    > php spark migrate -g test -n 'Acme\Blog'
 
 When using the ``--all`` option, it will scan through all namespaces attempting to find any migrations that have
 not been run. These will all be collected and then sorted as a group by date created. This should help