Not quite a mass replacement as I've used OS X and Mac OS X where
describing specific older versions and added compatibility methods
for things in the DSL.
This document lists Tigerbrew and Linuxbrew as interesting forks, not
branches (they used to be "Interesting Branches (aka forks)" but that
changed in b745546), so "Interesting Taps & Branches" is a more fitting
title.
The term "branches" is also presumably confusing to folks with a shallow
understanding of GitHub and/or git who may not realize how GitHub forks
and git branches are related.
Remove duplication, link to the API documentation more often,
tweak wording, add `@UniqMartin` as a maintainer, note `@jacknagel`'s
and `@adamv`'s significant past contributions to Homebrew, delete some
outdated or unneeded documentation, add some missing `Formula` API.
entries and simplify/improve `CONTRIBUTING.md`.
ClosesHomebrew/homebrew#46179.
ClosesHomebrew/homebrew#46618.
Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
