Fix macro.pp - macro output has changed slightly

Author: Munksgaard

test-project/tests/pretty/macro.pp

@@ -8,6 +8,6 @@
 // pretty-mode:expanded
 // pp-exact:macro.pp
 
-macro_rules! square(( $ x : expr ) => { $ x * $ x } ;);
+macro_rules! square { ($ x : expr) => { $ x * $ x } ; }
 
 fn f() -> i8 { 5 * 5 }