Make alternative clause parser more flexible.

The spirit here is to make it easier to discover this syntax. People
  have different intuition about it and the single pipe may not be the
  most obvious one.

  It is however the recommended syntax, and the formatter will rewrite
  any of the other to it.

crates/aiken-project/src/lib.rs

@@ -812,6 +812,10 @@ where
                     &mut self.data_types,
                 )?;
 
+                if name == "foo" {
+                    println!("{:#?}", checked_module.ast);
+                }
+
                 if our_modules.contains(checked_module.name.as_str()) {
                     self.warnings.extend(warnings);
                 }