message: Fix semver check for rust 1.54.0
  This updates semver.md to use the new error message for reporting missing
  generic arguments.
diff: @@ -943,7 +943,7 @@ pub fn foo<T, U>() {}
  use updated_crate::foo;
  fn main() {
  - foo::<u8>(); // Error: this function takes 2 type arguments but only 1 type argument was supplied
  + foo::<u8>(); // Error: this function takes 2 generic arguments but 1 generic argument was supplied
  }
  ```
  