typos in \babelposthyphenation should NOT remain silent

[ghost]

Running lualatex on

\documentclass{standalone}
\usepackage[USenglish]{babel}
\babelposthyphenation{USenglish}{in|sert}
{
  {}, {},        % in
  {pre=-, penatly=1000, data=2}, %%% a typo; „penatly“ doesn't exist
  {}, {}, {}, {} % sert
}
\showoutput
\begin{document}
  insert
\end{document}

doesn't raise any eyebrow: the misspelling penatly is silently swallowed. No warning, error, a message on undefined stuff, or a message on missing stuff is issued. The output is as if we had penalty=50 instead of penatly=1000. Such errors can be caught only if someone really turns on \showoutput and scrutinizes the output with the best of their eyesight.

We wish that any unknown stuff in \babelhyphenation is complained about, e.g., by issuing an error.

[jbezos]

And this isn’t the only case. Another one is \babelprovide, among others. I’ll improve it in the next versions.