Prevent simultaneous editing of comments and issues (#31053)

fixes #22907

Tested:
- [x] issue content edit
- [x] issue content change tasklist
- [x] pull request content edit
- [x] pull request change tasklist

![issue-content-edit](https://github.com/go-gitea/gitea/assets/29250154/a0828889-fb96-4bc4-8600-da92e3205812)

(cherry picked from commit aa92b13164e84c26be91153b6022220ce0a27720)

Conflicts:
	models/issues/comment.go
	 c7a389f2b2 [FEAT] allow setting the update date on issues and comments

	options/locale/locale_en-US.ini
	 trivial context conflicts

	routers/api/v1/repo/issue_comment.go
	routers/api/v1/repo/issue_comment_attachment.go
	services/issue/comments.go
	services/issue/content.go
         user blocking is implemented differently in Forgejo

	routers/web/repo/issue.go
	 trivial difference from 6a0750177f Allow to save empty comment
         user blocking is implemented differently in Forgejo

	templates/repo/issue/view_content/conversation.tmpl
	 templates changed a lot in Forgejo but the change is
	 trivially ported

	tests/integration/issue_test.go
	 other tests were added in the same region

	web_src/js/features/repo-issue-edit.js
	 the code is still web_src/js/features/repo-legacy.js
	 trivially ported

templates/repo/diff/comments.tmpl

@@ -61,7 +61,7 @@
 			{{end}}
 			</div>
 			<div id="issuecomment-{{.ID}}-raw" class="raw-content tw-hidden">{{.Content}}</div>
-			<div class="edit-content-zone tw-hidden" data-update-url="{{$.root.RepoLink}}/comments/{{.ID}}" data-context="{{$.root.RepoLink}}" data-attachment-url="{{$.root.RepoLink}}/comments/{{.ID}}/attachments"></div>
+			<div class="edit-content-zone tw-hidden" data-update-url="{{$.root.RepoLink}}/comments/{{.ID}}" data-content-version="{{.ContentVersion}}" data-context="{{$.root.RepoLink}}" data-attachment-url="{{$.root.RepoLink}}/comments/{{.ID}}/attachments"></div>
 			{{if .Attachments}}
 				{{template "repo/issue/view_content/attachments" dict "Attachments" .Attachments "RenderedContent" .RenderedContent}}
 			{{end}}