Update demo_output.md

Author: oblomov-dev

docs/development/specific/demo_output.md

@@ -1,4 +1,4 @@
-# cl_demo_output
+# CL_DEMO_OUTPUT
 
 You can also display the html output of the class cl_demo_output with abap2UI5. Take the following snippet ot see how it works:
 
@@ -94,4 +94,4 @@ METHOD z2ui5_if_app~main.
     client->view_display( view->stringify( ) ).
 
 ENDMETHOD.
-```
+```