Page for Reserved Keywords

[AustinEast]

I've recently been porting some code from another language to Haxe, and it happens to use a couple of Haxe's reserved keywords liberally. Its not a big blocker or anything, but I feel it would be helpful to document Haxe's current and planned reserved keywords, similar to the page that the old Haxe site had: http://old.haxe.org/ref/keywords

I'm willing to do the documentation if approved 👍

[Gama11]

Related: #319

[Gama11]

Actually, looks like this already exists, but as a subsection of the Expressions page:

https://haxe.org/manual/expression.html#keywords

[AustinEast]

Ah! Well I guess that settles it. I'd say that it could use more visibility, but that's not really my decision in the end 😄