share: i18n: fix mismatch in BIG5 esdb generation

In the first loop, we setup Big5_$i_variable where $i are elements of
$PART with : replaced to @.  Do the same in the second loop when we're
trying to refer to the same variable.

No functional change, because none of the in-tree mappings have an @
in them.

Sponsored by:	Klara, Inc.

share/i18n/esdb/BIG5/Makefile

@@ -16,7 +16,7 @@ Big5_$i_variable!= sed \
 # XXX: FIXME
 Big5-${i:S/:/@/}.src: Big5.src Big5.variable
 	sed -e 's/encoding/Big5-$i/' \
-		-e 's/variable/${Big5_$i_variable}/' \
+		-e 's/variable/${Big5_${i:S/@/:/}_variable}/' \
 		${.CURDIR}/Big5.src > $@
 	@echo ${.TARGET} >>.tmpfiles
 .endfor