Versioning Enhanced WGSL

(TBD)

As we stabilize for 1.0, we should mark a way for tools (and users) to distinguish our first stable version from subsequent releases.

Issues:

• Feature flags or versions? Consider also version
• perhaps version WESL2024?
• We’d like tools to maintain backward compatibility with previous stable versions. What do tools need?
• Look to rust editions as a model for versioning
• Look at WGSL discussion of similar topics, e.g. #2941