docs: fix view classname

Use the same classname as the above sample code.

Author: kenjis

user_guide_src/source/outgoing/view_cells.rst

@@ -113,7 +113,7 @@ You can also create a controlled cell via a built in command from the CLI. The c
 
 ::
 
-    > php spark make:cell AlertMessage
+    > php spark make:cell AlertMessageCell
 
 Using a Different View
 ======================