09c667eb45
Backport #22272. Fix #22270. Related to #18407. The old code treated both sitemap and sitemap index as the format like: ```xml ... <url> <loc>http://localhost:3000/explore/users/sitemap-1.xml</loc> </url> ... ``` Actually, it's incorrect for sitemap index, it should be: ```xml ... <sitemap> <loc>http://localhost:3000/explore/users/sitemap-1.xml</loc> </sitemap> ... ``` See https://www.sitemaps.org/protocol.html Co-authored-by: Lauris BH <lauris@nix.lv> Co-authored-by: delvh <dev.lh@web.de> Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>