Update shebang test notes

src/tests.rs

@@ -182,16 +182,16 @@ d: c
 #[test]
 fn shebang() {
   // this test exists to make sure that shebang recipes
-  // are run correctly. although it is still executed
+  // run correctly. although this script is still
-  // by sh its behavior depends on the value of a
+  // executed by sh its behavior depends on the value of a
-  // variable, which would not be available if it were
+  // variable and continuing even though a command fails
-  // a plain recipe
   let text = "
 a:
  #!/usr/bin/env sh
  code=200
  function x { return $code; }
  x
+ x
 ";
 
   match expect_success(text).run(&["a"]).unwrap_err() {