Enable gocritic equalFold and fix issues (#34952)

Continuation of https://github.com/go-gitea/gitea/pull/34678.

---------

Signed-off-by: silverwind <me@silverwind.io>

modules/markup/mdstripper/mdstripper.go

@@ -91,8 +91,7 @@ func (r *stripRenderer) processAutoLink(w io.Writer, link []byte) {
 	}
 
 	// Note: we're not attempting to match the URL scheme (http/https)
-	host := strings.ToLower(u.Host)
-	if host != "" && host != strings.ToLower(r.localhost.Host) {
+	if u.Host != "" && !strings.EqualFold(u.Host, r.localhost.Host) {
 		// Process out of band
 		r.links = append(r.links, linkStr)
 		return