add underline escape

src/controller/room.php

@@ -595,10 +595,16 @@ class Room
                 $line
             );
 
-            // Escape inline *
+            // Escape inline
             $line = preg_replace(
+                [
                     '/[*]{1}([^*]+)[*]{1}/',
+                    '/[_]{1}([^*]+)[_]{1}/',
+                ],
+                [
                     '[*]$1[*]',
+                    '[_]$1[_]',
+                ],
                 $line
             );