Write how to use bevy_egui_inspector on web

[janhohenheim]

Running trunk serve --features dev seems to ignore the features passed. I had to add the following to my index.html:

-    <link data-trunk rel="rust" data-cargo-no-default-features data-wasm-opt="s" href="../" />
+    <link data-trunk rel="rust" data-cargo-no-default-features data-cargo-features="dev" data-wasm-opt="s" href="../" />

but then I got greeted with the following:

it seems to me like there is no opt-out of that feature when using bevy_egui_inspector, which may be worth fixing upstream: jakobhellermann/bevy-inspector-egui#209 and jakobhellermann/bevy-inspector-egui#210. Until then, you indeed need to set your RUSTFLAGS env var:

RUSTFLAGS="--cfg=web_sys_unstable_apis"

I've seen people online say that you can add this to your config.toml, but I have not had success with that.

---

Technically we don't ship bevy_egui_inspector, but given that we highly recommend it, it may be worth making sure that people can actually use it.

[TheKnarf]

Add the following to to .cargo/config.toml:

[build]
rustflags = ["--cfg=web_sys_unstable_apis"]

I think this should probably just be a part of the template.

[janhohenheim]

@TheKnarf I don't know why, but that does not work on my Windows environment. Note that my config.toml works in general, so that's not the issue. I really had to set the environment variable.

[TheKnarf]

Hm, I got it working on MacOS. I haven't tested it on windows, but it also worked in the CI pipeline.