Remove misguided FALLTHROUGH comments

...between adjacent switch labels without any intervening statements

Change-Id: Ieb8a0d9f71ea4382b5f7d005cdf7111d06aeb5d0
Reviewed-on: https://gerrit.libreoffice.org/64789
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

cppcanvas/source/mtfrenderer/implrenderer.cxx

@@ -1273,7 +1273,6 @@ namespace cppcanvas
                         break;
 
                     case MetaActionType::TEXTLANGUAGE:
-                        // FALLTHROUGH intended
                     case MetaActionType::REFPOINT:
                         // handled via pCurrAct->Execute( &rVDev )
                         break;