NativeFunctionsIO.java Dead link on the manual page

[Jaccouille]

There is a dead link in this section to a NativeFunctionsIO.java file: https://wurstlang.org/manual.html#functions-available-at-compiletime

wurstscript.github.io/_doc/manual/concepts_advanced.md

Line 602 in a231eac

The currently implemented functions can be found in the compiler code in the class [NativeFunctionsIO](https://github.com/wurstscript/WurstScript/blob/master/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstio/jassinterpreter/NativeFunctionsIO.java).

I don' knowt what this file was supposed to contain and therefore didn't look for it.
Should use git to find out where it was replaced/displaced.

[Frotty]

They were split into their own classes, I adjusted that portion of the manual, thx.