`spin build` trigger validation messages are not explained

[itowlson]

I fouled up the Redis template so that trigger had a base field instead of address.

When I ran spin build, it said Error: missing field address``.

As my brain was in the "I am compiling" mindset, I assumed there was something wrong in the code, though I was puzzled by the lack of compiler context. It didn't occur to me for a while that Spin was actually validating the trigger configuration.

Could we either ignore irrelevant fields during build, or provide a contextful message such as "Invalid trigger configuration" or "Invalid manifest file", ideally saying more about where the error occurred than just the name of what in this case was a nested field? Even calling it trigger.address would have helped.

[dicej]

I think this could be a "good first issue" if we flesh it out a bit more, e.g. explaining where in the code to add context.