Correct the pacakge names of GCC12 for cross compiling

[lwhsu]

Summary

Correct the pacakge names of GCC12 for cross compiling

And use the newly added syntax of pacakge macro (in D39067)

[pauamma_chezdork.com]

documentation/content/en/articles/committers-guide/_index.adoc

3147

While here, noting the use of aarch64-gcc12 here and arm64-gcc12 below, which doesn't look right. If both are correct, a sentence stating that explicitly would reduce reader confusion.

3152

Probably out of scope for this, but noting grammar looks iffy here. Either s/The // or add whichever word is missing after "FreeBSD", perhaps "Project".

[lwhsu]

Fix typo