lang/ruby30: Fix plist error when both CAPIDOCS and DOCS options are on.

When the both options are on, post-install-DOCS-on target is called
after post-install-CAPIDOCS-on has completed. And in the former files
under ${WRKSRC}/doc/ are copied to ${STAGEDIR}${RUBY_DOCDIR}. This
means files under ${WRKSRC}/doc/capi are copied to
${STAGEDIR}${RUBY_DOCDIR}/capi again. And of course
${WRKSRC}/doc/capi/.timestamp is included in them. As a result, even
though ${STAGEDIR}${RUBY_DOCDIR}/capi/.timestamp is removed in
post-install-CAPIDOCS-on target, it is detected as orphaned file at
check-plist phase. So fix it by adding 3rd argument to
${COPYTREE_SHARE} command so .timestamp is excluded from files to be
copied.

PR:		267775
Approved by:	meta (ruby@)
Fixes:		93e3548 lang/ruby30: Simplify CAPIDOCS handling

lang/ruby30/Makefile

@@ -196,7 +196,7 @@ post-install-DOCS-on:
 	${INSTALL_DATA} ${WRKSRC}/ext/${FILE} \
 		${STAGEDIR}${RUBY_DOCDIR}/${FILE:C|^([^/]+)/.*|\1|}/
 .endfor
-	@(cd ${WRKSRC}/doc/ && ${COPYTREE_SHARE} \* ${STAGEDIR}${RUBY_DOCDIR}/)
+	@(cd ${WRKSRC}/doc/ && ${COPYTREE_SHARE} \* ${STAGEDIR}${RUBY_DOCDIR}/ "! -name .timestamp")
 	${INSTALL_DATA} ${WRKSRC}/COPYING*	\
 			${WRKSRC}/ChangeLog	\
 			${WRKSRC}/LEGAL		\