[turborepo] Document behavior for how a failing task interacts with the cache

[closesimple-wl]

What version of Turborepo are you using?

1.10.12

What package manager are you using / does the bug impact?

pnpm

What operating system are you using?

Mac

Describe the Bug

The documentation needs to spell out how a failing task is not cached. Not to mention, there's no API to force caching a failed result.

This might be implied, but it's definitely not clear nor explicit, and we shouldn't have to do mental gymnastics to figure out the reasoning behind the software's behavior.

Expected Behavior

A clear explanation in the docs. Only a few sentences is needed, really.

To Reproduce

Run a task whose scripts definition is exit 1.

Reproduction Repo

No response

[tknickman]

Closed via #5782

[closesimple-wl]

That's better, but it still doesn't explain the reasoning.