Some tweaks on CATCH (#4050)
Some tweaks on CATCH (#4050)

* Some tweaks on CATCH

In resoponse to https://github.com/Raku/doc/issues/4049

* typo

* Pass example compilation test

declare some items in preamble. Cheat on the method invocation.
use =begin on nearby block for consistent source formatting

Co-authored-by: Coke <37d41699bdee4fcb969ca499eb0f8b82c60d59cc@coleda.com>
tbrowder/doc,MasterDuke17/doc,MasterDuke17/doc,MasterDuke17/doc,MasterDuke17/doc,tbrowder/doc,tbrowder/doc,tbrowder/doc