local and global artifacts job configs have inconsistent names

I didn't really notice at the time, but [the docs for custom build jobs](https://opensource.axo.dev/cargo-dist/book/reference/config.html#build-global-artifacts-jobs) say that "build-local-artifacts-jobs" and "build-global-artifacts-jobs" are the names of these configs, but in fact they're "local-artifacts-jobs" and "global-artifacts-jobs".

The actual builtin CI task is "build-local-artifacts" and "build-global-artifacts", so the docs have the more consistent name. However, I'm coming around to a belief that these should be renamed to just "build-local" and "build-global" because "artifacts" is redundant and crowds out precious space in various UIs. (and then the config would be "build-local-jobs" and "build-global-jobs")

tbc this is "we have 2 names and i hate them both, let's use this 3rd name" (we can add as many aliases as we want for the configs)

Start with the custom build jobs documentation linked in the issue and compare its config names with the actual builtin CI task names. Decide whether the configs should retain aliases or adopt the proposed build-local-jobs and build-global-jobs names; the work is done when the naming decision is implemented consistently in the configuration and documentation.

Written by the indexing model from the issue text.