runtime(forth): Update syntax and ftplugin files (#12976)

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 4fafc7c..0cde277 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -133,6 +133,7 @@
 runtime/ftplugin/expect.vim		@dkearns
 runtime/ftplugin/fennel.vim		@gpanders
 runtime/ftplugin/fetchmail.vim		@dkearns
+runtime/ftplugin/forth.vim		@jkotlinski
 runtime/ftplugin/fpcmake.vim		@dkearns
 runtime/ftplugin/freebasic.vim		@dkearns
 runtime/ftplugin/fstab.vim		@rid9