Make issue meta dropdown support Enter, confirm before reloading (#23014)

As the title. Label/assignee share the same code.

* Close #22607
* Close #20727

Also:

* partially fix for #21742, now the comment reaction and menu work with
keyboard.
* partially fix for #17705, in most cases the comment won't be lost.
* partially fix for #21539
* partially fix for #20347
* partially fix for #7329

### The `Enter` support

Before, if user presses Enter, the dropdown just disappears and nothing
happens or the window reloads.

After, Enter can be used to select/deselect labels, and press Esc to
hide the dropdown to update the labels (still no way to cancel ....
maybe you can do a Cmd+R or F5 to refresh the window to discard the
changes .....)


This is only a quick patch, the UX is still not perfect, but it's much
better than before.


### The `confirm` before reloading

And more fixes for the `reload` problem, the new behaviors:

* If nothing changes (just show/hide the dropdown), then the page won't
be reloaded.
* If there are draft comments, show a confirm dialog before reloading,
to avoid losing comments.

That's the best effect can be done at the moment, unless completely
refactor these dropdown related code.

Screenshot of the confirm dialog:

<details>


![image](https://user-images.githubusercontent.com/2114189/220538288-e2da8459-6a4e-43cb-8596-74057f8a03a2.png)

</details>

---------

Co-authored-by: Brecht Van Lommel <brecht@blender.org>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

3 files changed, 7 insertions, 7 deletions

diff --git a/templates/repo/issue/view_content/add_reaction.tmpl b/templates/repo/issue/view_content/add_reaction.tmpl
index 9bd9022d2..bfa8a7e12 100644
--- a/templates/repo/issue/view_content/add_reaction.tmpl
+++ b/templates/repo/issue/view_content/add_reaction.tmpl
@@ -7,7 +7,7 @@
 		<div class="header">{{.ctx.locale.Tr "repo.pick_reaction"}}</div>
 		<div class="divider"></div>
 		{{range $value := AllowedReactions}}
-			<div class="item reaction tooltip" data-content="{{$value}}">{{ReactionToEmoji $value}}</div>
+			<a class="item reaction tooltip" data-content="{{$value}}">{{ReactionToEmoji $value}}</a>
 		{{end}}
 	</div>
 </div>
diff --git a/templates/repo/issue/view_content/context_menu.tmpl b/templates/repo/issue/view_content/context_menu.tmpl
index b96fd86af..b4b9403b2 100644
--- a/templates/repo/issue/view_content/context_menu.tmpl
+++ b/templates/repo/issue/view_content/context_menu.tmpl
@@ -10,16 +10,16 @@
 		{{else}}
 			{{$referenceUrl = Printf "%s/files#%s" .ctx.Issue.Link .item.HashTag}}
 		{{end}}
-		<div class="item context" data-clipboard-text-type="url" data-clipboard-text="{{AppSubUrl}}{{$referenceUrl}}">{{.ctx.locale.Tr "repo.issues.context.copy_link"}}</div>
-		<div class="item context quote-reply {{if .diff}}quote-reply-diff{{end}}" data-target="{{.item.HashTag}}-raw">{{.ctx.locale.Tr "repo.issues.context.quote_reply"}}</div>
+		<a class="item context" data-clipboard-text-type="url" data-clipboard-text="{{AppSubUrl}}{{$referenceUrl}}">{{.ctx.locale.Tr "repo.issues.context.copy_link"}}</a>
+		<a class="item context quote-reply {{if .diff}}quote-reply-diff{{end}}" data-target="{{.item.HashTag}}-raw">{{.ctx.locale.Tr "repo.issues.context.quote_reply"}}</a>
 		{{if not .ctx.UnitIssuesGlobalDisabled}}
-			<div class="item context reference-issue" data-target="{{.item.HashTag}}-raw" data-modal="#reference-issue-modal" data-poster="{{.item.Poster.GetDisplayName}}" data-poster-username="{{.item.Poster.Name}}" data-reference="{{$referenceUrl}}">{{.ctx.locale.Tr "repo.issues.context.reference_issue"}}</div>
+			<a class="item context reference-issue" data-target="{{.item.HashTag}}-raw" data-modal="#reference-issue-modal" data-poster="{{.item.Poster.GetDisplayName}}" data-poster-username="{{.item.Poster.Name}}" data-reference="{{$referenceUrl}}">{{.ctx.locale.Tr "repo.issues.context.reference_issue"}}</a>
 		{{end}}
 		{{if or .ctx.Permission.IsAdmin .IsCommentPoster .ctx.HasIssuesOrPullsWritePermission}}
 			<div class="divider"></div>
-			<div class="item context edit-content">{{.ctx.locale.Tr "repo.issues.context.edit"}}</div>
+			<a class="item context edit-content">{{.ctx.locale.Tr "repo.issues.context.edit"}}</a>
 			{{if .delete}}
-				<div class="item context delete-comment" data-comment-id={{.item.HashTag}} data-url="{{.ctx.RepoLink}}/comments/{{.item.ID}}/delete" data-locale="{{.ctx.locale.Tr "repo.issues.delete_comment_confirm"}}">{{.ctx.locale.Tr "repo.issues.context.delete"}}</div>
+				<a class="item context delete-comment" data-comment-id={{.item.HashTag}} data-url="{{.ctx.RepoLink}}/comments/{{.item.ID}}/delete" data-locale="{{.ctx.locale.Tr "repo.issues.delete_comment_confirm"}}">{{.ctx.locale.Tr "repo.issues.context.delete"}}</a>
 			{{end}}
 		{{end}}
 	</div>
diff --git a/templates/repo/issue/view_content/sidebar.tmpl b/templates/repo/issue/view_content/sidebar.tmpl
index 2b24825b5..d9c506243 100644
--- a/templates/repo/issue/view_content/sidebar.tmpl
+++ b/templates/repo/issue/view_content/sidebar.tmpl
@@ -121,7 +121,7 @@
 						<input type="text" placeholder="{{.locale.Tr "repo.issues.filter_labels"}}">
 					</div>
 				{{end}}
-				<div class="no-select item">{{.locale.Tr "repo.issues.new.clear_labels"}}</div>
+				<a class="no-select item" href="#">{{.locale.Tr "repo.issues.new.clear_labels"}}</a>
 				{{if or .Labels .OrgLabels}}
 					{{$previousExclusiveScope := "_no_scope"}}
 					{{range .Labels}}