Update docs: running a custom Node.js TiddlyWiki version with npx

Author: shadow

editions/tw5.com/tiddlers/nodejs/Installing TiddlyWiki on Node.js.tid

@@ -39,4 +39,6 @@ The `-g` flag causes TiddlyWiki to be installed globally. Without it, TiddlyWiki
 
 <<.warning "If you are using Debian or Debian-based Linux and you are receiving a `node: command not found` error though node.js package is installed, you may need to create a symbolic link between `nodejs` and `node`. Consult your distro's manual and `whereis` to correctly create a link. See github [[issue 1434|http://github.com/TiddlyWiki/TiddlyWiki5/issues/1434]]. <br><br>Example Debian v8.0: `sudo ln -s /usr/bin/nodejs /usr/bin/node`">>
 <br>
-<<.tip "You can also install prior versions like this: <br><code> npm install -g tiddlywiki@5.1.13</code>">>
+<<.tip "You can also install prior versions like this: <br><code> npm install -g tiddlywiki@5.1.13</code><br>Note: this will overwrite the installed version rather than installing it alongside.">>
+<br>
+<<.tip "To run another version without overwriting the currently installed version, use npx: <br><code>npx tiddlywiki@5.3.8 --version</code>">>