Add Reflect and FromReflect for AssetPath

[minchopaskal]

Objective

• Add Reflect and FromReflect for AssetPath
• Fixes Reflect for AssetPath #8458

Solution

• Straightforward derive of Reflect and FromReflect for AssetPath
• Implement Reflect and FromReflect for Cow<'static, Path> as to satisfy the 'static lifetime requierments of bevy_reflect. Implementation is a direct copy of that for Cow<'static, str> so maybe it begs the question that was already asked in bevy_reflect: Support Cow<'static, [T]> #7429 - maybe it would be benefitial to write a general implementation for Reflect for Cow<'static, T>.

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[alice-i-cecile]

I'm in favor of the general form TBH.

[MrGVSV]

Not sure we could have a blanket impl like that. I think the main concern is that we lock ourselves into a single ReflectKind (besides possible issues with the blanket impl itself). It already wouldn't work since we want Cow<'static, str> to be a Value but we also want Cow<'static, [T]> to be a List.

[MrGVSV]

Just a few comments.

Also, I agree that we could maybe reduce the code duplication (maybe a macro_rules for &'static T/Cow<'static, T>?), but that can be done in a separate PR.

[MrGVSV]

Sorry two more comments I forgot to leave 😅

[MrGVSV]

Looks good! Thanks for doing this!

[minchopaskal]

My pleasure!

[alice-i-cecile]

@minchopaskal can you please resolve comments that you've addressed to make things easier for further reviewers to follow?

[minchopaskal]

@alice-i-cecile done. Sorry! I made the assumption that the one who leaves comments should resolve them.

[alice-i-cecile]

Totally fine, it's just an arbitrary cultural choice we've made :)