explicitly mention compile-time options of logging crates for code-size reduction

[hmeine]

I found it possible to shave more than 1% off my already optimized .wasm size by using the release_max_level_off feature on the tracing crate. Hence, I suggest to extend the section that already mentions string formatting as a potential vector for code size reduction to point to these features, since tracing and log are commonly used (also indirectly in dependencies – bevy in my case).