Function user_message 

pub fn user_message(err: &Error) -> String

A user-facing message for an error that came out of running Lua: the innermost cause without Lua’s stack traceback: block. A host function’s Err(e) surfaces as e’s own text; a Lua error("msg") surfaces as file:line: msg.

sgen: content/no-date.md: front matter: 'date' is required

instead of that line followed by stack traceback: [C]: in method 'pages' ....