expose translation of previously hardcoded string (#14087)

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

options/locale/locale_en-US.ini

@@ -654,6 +654,7 @@ email_notifications.submit = Set Email Preference
 
 [repo]
 owner = Owner
+owner_helper = Some organizations may not show up in the dropdown due to a maximum repository count limit.
 repo_name = Repository Name
 repo_name_helper = Good repository names use short, memorable and unique keywords.
 repo_size = Repository Size

templates/repo/create.tmpl

@@ -31,7 +31,7 @@
 								{{end}}
 							</div>
 						</div>
-						<span class="help">Some organizations may not show up in the dropdown due to a maximum repository count limit</span>
+						<span class="help">{{.i18n.Tr "repo.owner_helper"}}</span>
 					</div>
 
 					<div class="inline required field {{if .Err_RepoName}}error{{end}}">