Update ssh_config.md

updated ports regular expression to allow only ports numbers from 1 to 65536

doc/ssh_config/ssh_config.md

@@ -155,7 +155,7 @@ module sonic-ssh-server {
 					description "ssh port numbers";
 					default "22";
                     type string {
-                        pattern '[1-9]\d{0,4}(,[1-9]\d{0,4})*' {
+                        pattern '([1-9]|[1-9]\d{1,3}|[1-5]\d{4}|6[0-4]\d{3}|65[0-4]\d{2}|655[0-2]\d|6553[0-6])(,([1-9]|[1-9]\d{1,3}|[1-5]\d{4}|6[0-4]\d{3}|65[0-4]\d{2}|655[0-2]\d|6553[0-6]))*' {
                             error-message "Invalid port numbers value";
                             error-app-tag ssh-server-ports-invalid-value;
                         }