Improve text of some errors

[Mingun]

This PR improves text of errors and partially implements this TODO:

// TODO: get rid of MethodNotFoundError in favor of MethodNotFoundErrorWithArg, rename it back

In all situations where MethodNotFoundErrorWithArg could be thrown it is thrown. Also I added new MethodTypeArg for kaitai stream type.

PR for updating tests: https://github.com/kaitai-io/kaitai_struct_tests/pull/129