[docs] Add onMakeDirectory and onMakeSymlink to the list of tracking delegates

[WebCoder49]

This is to match the example code below that list, which contains onMakeDirectory and onMakeSymlink, while they are absent from the list above.

Reading only the list and not the example code below it, I was confused about how to track directory creation, and this pull request should resolve that confusion for others.

[sbc100]

lgtm.

BTW, do you use the trackingDelegate? I was wondering if it had any users, and what they uses it for. Since its only available with FS_DEBUG its uses seem pretty limited.

[WebCoder49]

I'm writing a code editor which uses Pyodide (an Emscripten port of the CPython interpreter) to run code. I use the trackingDelegate with Pyodide's filesystem, to then synchronise with both the editor's UI and Yjs for peer-to-peer collaboration.

[sbc100]

I see, so use are using the in memory emscripen FS, but want to reflect that out to something outside (in this case the UI?) I guess that means you need to build with FS_DEBUG even in your release build? I wonder if this the best solution for you use case or if we could come up with a way to intercept arbitrary system calls / library calls?

[WebCoder49]

Good question, @sbc100. It looks like Pyodide insalled via NPM defaults to the debug build anyway, so initially I didn't even notice I was running the debug build. Is there any major issue to having the debug build of Emscripten, especially if it is being used as a development environment?

[WebCoder49]

It looks like the Raspberry Pi's editor which also uses Pyodide intercepts file opens at the Python level. Nevertheless, I think it may be difficult to ensure the interception is complete especially when importing C-language libraries into Python or dealing with directories.

[WebCoder49]

(Sorry for taking your time; you don't have to respond.)