Respec postcircumfix:<( )> to take arguments directly

This makes it possible to implement it as a set of multi methods.

Author: sorear

S13-overloading.pod

@@ -137,13 +137,13 @@ is better written:
 A class may define methods that allow it to respond as if it were a
 routine, array, or hash.  The long forms are as follows:
 
-    method postcircumfix:<( )> ($capture) {...}
+    method postcircumfix:<( )> (|capture) {...}
     method postcircumfix:<[ ]> (**@slice) {...}
     method postcircumfix:<{ }> (**@slice) {...}
 
 Those are a bit unwieldy, so you may also use these short forms:
 
-    method &.( $capture ) {...}
+    method &.( |capture ) {...}
     method @.[ **@slice ] {...}
     method %.{ **@slice } {...}