Improve "Reference in new issue" modal (#30547)

Fixes: https://github.com/go-gitea/gitea/issues/29994

Also some misc enhancements done to the form in the modal.

<img width="840" alt="Screenshot 2024-04-17 at 23 02 55"
src="https://github.com/go-gitea/gitea/assets/115237/e71fba55-55cd-4e48-a497-6b1025c36a43">

templates/repo/issue/view_content/reference_issue_dialog.tmpl

@@ -5,26 +5,24 @@
 	<div class="content tw-text-left">
 		<form class="ui form form-fetch-action" action="{{printf "%s/issues/new" .Repository.Link}}" method="post">
 			{{.CsrfTokenHtml}}
-			<div class="ui segment content">
 			<div class="field">
-					<span class="text"><strong>{{ctx.Locale.Tr "repository"}}</strong></span>
-					<div class="ui search normal selection dropdown issue_reference_repository_search">
+				<label><strong>{{ctx.Locale.Tr "repository"}}</strong></label>
+				<div class="ui search selection dropdown issue_reference_repository_search">
 					<div class="default text">{{.Repository.FullName}}</div>
 					<div class="menu"></div>
 				</div>
 			</div>
 			<div class="field">
-					<span class="text"><strong>{{ctx.Locale.Tr "repo.milestones.title"}}</strong></span>
+				<label><strong>{{ctx.Locale.Tr "repo.milestones.title"}}</strong></label>
 				<input name="title" value="" autofocus required maxlength="255" autocomplete="off">
 			</div>
 			<div class="field">
-					<span class="text"><strong>{{ctx.Locale.Tr "repo.issues.reference_issue.body"}}</strong></span>
+				<label><strong>{{ctx.Locale.Tr "repo.issues.reference_issue.body"}}</strong></label>
 				<textarea name="content" class="form-control"></textarea>
 			</div>
 			<div class="text right">
 				<button class="ui primary button">{{ctx.Locale.Tr "repo.issues.create"}}</button>
 			</div>
-			</div>
 		</form>
 	</div>
 </div>

web_src/css/base.css

@@ -374,6 +374,7 @@ a.label,
 
 .ui.selection.dropdown .menu > .item {
   border-color: var(--color-secondary);
+  white-space: nowrap;
 }
 
 .ui.selection.visible.dropdown > .text:not(.default) {
@@ -390,6 +391,12 @@ a.label,
   color: var(--color-text-light-2);
 }
 
+.ui.dropdown > .text {
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
 /* extend fomantic style '.ui.dropdown > .text > img' to include svg.img */
 .ui.dropdown > .text > .img {
   margin-left: 0;