fixed typo in README.md

Author: clickkiddie

README.md

@@ -133,7 +133,7 @@ One or more trusted domains can be set by environment variable, too. They will b
 
 - `NEXTCLOUD_TRUSTED_DOMAINS` (not set by default) Optional space-separated list of domains
 
-Reverse proxy configuration according to [Admin Manual] (https://docs.nextcloud.com/server/13/admin_manual/configuration_server/reverse_proxy_configuration.html) can be achieved using:
+Reverse proxy configuration according to [Admin Manual](https://docs.nextcloud.com/server/13/admin_manual/configuration_server/reverse_proxy_configuration.html) can be achieved using:
 - `NEXTCLOUD_OVERWRITEPROTOCOL` (not set by default) Optional overwrite protocol (e.g. https)
 - `NEXTCLOUD_OVERWRITEHOST` (not set by default) Optional overwrite host (e.g. nextcloud.examle.com)
 - `NEXTCLOUD_OVERWRITEWEBROOT` (not set by default) Optional overwrite webroot (e.g. /cloud)