Incorrect "missing argument at end of command" error

[blyxxyz]

This code:

fn main() -> Result<(), lexopt::Error> {
    let mut parser = lexopt::Parser::from_env();
    parser.values()?;
    Ok(())
}

Has this behavior:

$ cargo run -- -a b
Error: missing argument at end of command

This is Error::MissingValue's message if Parser doesn't remember an option. In 0.1.0 it was only returned by Parser::value(), at the end of the command line, but Parser::values() may return it if it encounters an option.

An easy fix would be to remove "at end of command" from the message, but maybe there's a better way out.

[blyxxyz]

A reasonable program would only cause a MissingValue after seeing an option, in which case this version of the message isn't used. So removing "at end of command" doesn't do much harm.

Fixed in 614d714.