git-sh-i18n: remove unused eval_ngettext()

The "eval_ngettext()" function has been orphaned since its last user
was removed in a74b35081c (rebase: drop support for
`--preserve-merges`, 2021-09-07).

See b8fc9e43a7 (i18n: rebase-interactive: mark here-doc strings for
translation, 2016-06-17) for the commit that added these
eval_ngettext() wrappers.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-sh-i18n.sh

@@ -51,12 +51,6 @@ gettext_without_eval_gettext)
 		)
 	}
 
-	eval_ngettext () {
-		ngettext "$1" "$2" "$3" | (
-			export PATH $(git sh-i18n--envsubst --variables "$2");
-			git sh-i18n--envsubst "$2"
-		)
-	}
 	;;
 *)
 	gettext () {
@@ -70,12 +64,6 @@ gettext_without_eval_gettext)
 		)
 	}
 
-	eval_ngettext () {
-		(test "$3" = 1 && printf "%s" "$1" || printf "%s" "$2") | (
-			export PATH $(git sh-i18n--envsubst --variables "$2");
-			git sh-i18n--envsubst "$2"
-		)
-	}
 	;;
 esac