Serialization of Module

[kvark]

I was thinking that it would be great to be able to save (and load?) RON files by the converter. The joys of RON is that it's very nice to inspect visually (by humans):

• array elements have index numbers, which is critical for associating them with Handle(xxx) values through the rest of the module
• nice representation of maps and enums
• otherwise similar to pretty Debug implementation
• ability to just tweak it by hand

To get this, we need a serde optional feature, implementation of Serialize+Deserialize for all IR objects, and also gfx-rs/rspirv#123 resolved.

[paulkernfeld]

Should this have separate serialize and deserialize features as in gfx-rs/rspirv#123, or is it fine to just have a single serde feature for both?

[kvark]

In general, it would be better to separate serialization from deserialization, since the latter is taking way more compile time. This would also let us avoid conflicting the serde feature with optional dependency.