Update Distribution guide;

guides/Distribution.md

@@ -61,8 +61,9 @@ Emscripten SDK:
 $ python "$EMSCRIPTEN/tools/file_packager.py" game.data --no-heap-copy --preload /path/to/game@/ --js-output=game.js
 ```
 
-This will output two files: `game.js` and `game.data`.  The `game.js` file downloads the `game.data`
-contents and mounts it into the Emscripten filesystem, which LÖVR will then run at startup.
+This will output two files: `game.js` and `game.data` (note that the `@/` suffix is important).  The
+`game.js` file downloads the `game.data` contents and mounts it into the Emscripten filesystem,
+which LÖVR will then run at startup.
 
 For full instructions on creating a web-enabled build of LÖVR, see the [Compiling guide](Compiling#webvr).
 You can also use [lovr-webvr-server](https://github.com/bjornbytes/lovr-webvr-server) to develop a