Add RFC for shorter vector constructor

[petrihakkinen]

Add RFC for replacing the current vector constructor (vector.create) with a less verbose version (vector).

Rendered

[petrihakkinen]

After a long think I decided to propose the deprecation and eventual removal of vector.create in favor of vector in the RFC because I think it would be better for the language in the long run to have only one constructor. If you think this is a too big breaking change we can modify the RFC to keep the old version as an alias. I don't have a strong opinion on that but we'd prefer some officially sanctioned way to disable vector.create (or any other built-in) locally for our codebase in case vector is added but vector.create is not deprecated.

[jackdotink]

Personally I would like to see special syntax for creating vectors, such as <x, y, z>.

[vegorov-rbx]

I don't think we will be adopting this.
Reasoning for current constructor was already discussed in the vector library RFC and we have selected that option to go forward.

In a way, this RFC was already rejected in the discussion of that RFC.