Fix footnote jump behavior on the issue page. (#34621)

Close #34511 
Close #34590 

Add comment ID to the footnote item's id attribute to ensure uniqueness.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/web/repo/issue_comment.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"html/template"
 	"net/http"
+	"strconv"
 
 	issues_model "code.gitea.io/gitea/models/issues"
 	"code.gitea.io/gitea/models/renderhelper"
@@ -278,7 +279,9 @@ func UpdateCommentContent(ctx *context.Context) {
 
 	var renderedContent template.HTML
 	if comment.Content != "" {
-		rctx := renderhelper.NewRenderContextRepoComment(ctx, ctx.Repo.Repository)
+		rctx := renderhelper.NewRenderContextRepoComment(ctx, ctx.Repo.Repository, renderhelper.RepoCommentOptions{
+			FootnoteContextID: strconv.FormatInt(comment.ID, 10),
+		})
 		renderedContent, err = markdown.RenderString(rctx, comment.Content)
 		if err != nil {
 			ctx.ServerError("RenderString", err)