doc: add missing proxy header in reverse-proxy.md (#8260)

fix: add missing nginx proxy header

Signed-off-by: Clément Pivot <8830707+Clement-Pivot@users.noreply.github.com>

reverse-proxy.md

@@ -523,6 +523,7 @@ server {
     location / {
         proxy_pass http://127.0.0.1:11000$request_uri; # Adjust to match APACHE_PORT and APACHE_IP_BINDING. See https://github.com/nextcloud/all-in-one/blob/main/reverse-proxy.md#adapting-the-sample-web-server-configurations-below
 
+        proxy_set_header X-Forwarded-Host $host;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         proxy_set_header X-Forwarded-Port $server_port;
         proxy_set_header X-Forwarded-Scheme $scheme;