Specify docs of `Sys.exit()` for eval (closes #7217)

std/Sys.hx

@@ -100,6 +100,9 @@ extern class Sys {
 
 	/**
 		Exit the current process with the given error code.
+
+		(macro)(eval) Being invoked in a macro or eval context (e.g. with `-x` or `--run`) immediately terminates
+		the compilation process also preventing the execution of any `--next` section of compilation arguments.
 	**/
 	static function exit( code : Int ) : Void;