refactor(doc/contributing): improve descriptions/sections

[PsychoShock]

This should be more clear for users now.

[PsychoShock]

I was thinking probably adding the tables method, just like https://github.com/citizenfx/natives/pull/977#pullrequestreview-1830851887. @4mmonium what do you think?

[PsychoShock]

This should now be good @4mmonium

I added the section method signature so people will know the standart from now.

[AvarianKnight]

I don't entirely see the point of this PR, this in my opinion, makes things harder to understand.

1. If we want an issue template we should specifically add one, burying it CONTRIBUTING.md seems like a bad idea.
2. Changing the examples at the bottom to improper format (Lua codegen will always be UpperCamelCase so randomly using UPPER_SNAKE_CASE is confusing)
3. Un-needed note about RedM native docs not being supported

Going to close this for now, some of this will hopefully get touched on later.