Many contributors don't have a Mono setup available, especially if
compiling from source is required.
Minimal reproduction projects in GDScript are also better at isolating
the actual bug, since it automatically rules out any possible C#
integration issues.
- Improve the bug reporting guidelines for readability.
- Make some guidelines more strictly applied in the interest of
bug report quality.
- Mention that feature proposals should now be opened on the
Godot Proposals repository.
- Update the Git commit message guide to be easier to follow.
- Fix warnings reported by markdownlint.
CONTRIBUTING.md would use the phrase "those guidelines" to introduce a
list. In general, the word "these" is used to refer to something that is
being introduced or has recently been introduced, and "those" is used to
refer to something that had been previously introduced.
This change also makes CONTRIBUTING.md consistent with the
documentation. The documentation guidelines at
https://docs.godotengine.org/en/latest/community/contributing/documentation_guidelines.html
use "these" to introduce a list and its singular form, "this", to
introduce items.
