Document alternatives to some static Color methods

[KoBeWi]

See godotengine/godot-proposals#10294

[AThousandShips]

We should probably see about how to document this constructor properly, as it's overlooked due to some conversion details, but this is good as an initial step IMO

[KoBeWi]

Another thing is that there is no way to link to a constructor, like to methods and members.

[Mickeon]

There is, but it's not coded properly because it's not standard (it needs more parameters than just the constructor's name)

Both [constructor Color] and [operator Color] work partially. They only point to the first one in the list if I recall correctly, and fail the check on Github.

[KoBeWi]

Yeah I noticed the constructors have name field, but each one is named the same. Hence it's effectively not possible to utilize it in a useful way.

[akien-mga]

Thanks!