Add documentation describing how to set up Xcode debugging

[gfx-rs]

Add documentation describing how to set up Xcode debugging

[chinedufn]

Quick update. I plan to do this whenever I need to use Metal's debugging tools.

No idea when that will be - but when it happens I'll PR a markdown file with some screenshots and maybe @kvark can take that and copy paste it into a Wiki for this repo (although I personally prefer either docs/some-markdown-files.md or an mdbook but I don't have a strong opinion here so whatever works!)

[kvark]

Thank you for filing your thoughts here!

We've been using XCode extensively in gfx/wgpu land to debug Metal pure-Rust applications. There is no need to have any infrastructure to do so, or any dedicated example.
There was a nice picture showing how to set it up somewhere (cc @grovesNL). Perhaps all we need is to make a Wiki page with a few pictures describing this?

The steps are basically:

1. Create a new project with "External Build System" type and "$(HOME)/.cargo/bin/cargo" tool
2. Edit Scheme -> Info -> Executable point to the executable you build
3. Optionally set up the environment, arguments (in Arguments) and working dir (in Options)

That's it!

[chinedufn]

Woah - that’s awesome!

A wiki page describing this sounds good to me. Along with a link to it from the README.

Sweet - glad this turned out to be even easier than I originally thought

[chinedufn]

Going to leave this open until I move the docs from the markdown file to the wiki as discussed in #151 (review)

[kvark]

@chinedufn you don't have to. I just wanted to make sure that you can do that, but if you prefer the markdown in code, I'm totally fine with that too.

[chinedufn]

Oh - sweet I'm leaving it as markdown then.

Cheers!