Improve spin watch

[calebschoepp]

Changes made

• Add a README to the example I added
• More accurate description text for spin watch command
• Remove all the complicated flags and only offer a --skip-build flag to support the non-default use case i.e. you want to run build yourself
• Remove TODO item for live reconfiguring watcher. I spent the afternoon spiking this and it was really messy and made the code super hard to read. I'm not convinced it is worth adding this until people start asking for it.

Example use cases

spin watch

• Watches what you've configured in component.build.watch and your component.files
• Runs both build and up

spin watch --skip-build

• Watches your component.source and your component.files
• Runs only up

[itowlson]

I'm wondering if I just haven't quite clicked into the mental model of the watch settings because it's not yet quite clear to me how these options fit together. I'm wondering what the impact would be of expressing it in terms of "what changes do I want to cause a restart" (assets, Wasm, source code) - would it be clearer or more confusing? (Like the "skip-build" setting is I think saying I don't want source code changes to cause a restart. Except that "watch-wasm" seems to be saying that too.)

(But I am also a bit vague on skip-up so I guess it's not just that.)

[calebschoepp]

@itowlson I pushed some fixes for all the comment threads we had going and I'm ready for re-review.

[itowlson]

Thanks! A few nits/suggestions but nothing that needs to block getting this into 1.1 - happy to revisit in future polishing/refactoring passes. Looks good!

[itowlson]

You should know the path of the manifest; use that instead of the literal text "spin.toml"