Change `add_on` in `keys_ssh.tmpl` (#24803)

Follow #24562

templates/user/settings/keys_ssh.tmpl

@@ -59,7 +59,7 @@
 								{{.Fingerprint}}
 						</div>
 						<div class="activity meta">
-								<i>{{$.locale.Tr "settings.add_on" (DateTime "short" .CreatedUnix) | Safe}} —	{{svg "octicon-info"}} {{if .HasUsed}}{{$.locale.Tr "settings.last_used"}} <span {{if .HasRecentActivity}}class="green"{{end}}>{{DateTime "short" .UpdatedUnix}}</span>{{else}}{{$.locale.Tr "settings.no_activity"}}{{end}}</i>
+								<i>{{$.locale.Tr "settings.added_on" (DateTime "short" .CreatedUnix) | Safe}} —	{{svg "octicon-info"}} {{if .HasUsed}}{{$.locale.Tr "settings.last_used"}} <span {{if .HasRecentActivity}}class="green"{{end}}>{{DateTime "short" .UpdatedUnix}}</span>{{else}}{{$.locale.Tr "settings.no_activity"}}{{end}}</i>
 						</div>
 				</div>
 			</div>