Unify and simplify TrN for i18n (#18141)

Refer: https://github.com/go-gitea/gitea/pull/18135#issuecomment-1003246099

Now we have a unique and simple `TrN`, and make the fix of PR #18135 also use the better `TrN` logic.

templates/repo/blame.tmpl

@@ -3,7 +3,7 @@
 		<div class="file-header-left df ac">
 			<div class="file-info text grey normal mono">
 				<div class="file-info-entry">
-					{{.NumLines}} {{.i18n.Tr (TrN .i18n.Lang .NumLines "repo.line" "repo.lines") }}
+					{{.NumLines}} {{.i18n.TrN .NumLines "repo.line" "repo.lines"}}
 				</div>
 				<div class="file-info-entry">{{FileSize .FileSize}}</div>
 			</div>