It seems that `ul` can't handle the escape sequences for bold text that `nroff` generates on my system. Fixed by either removing `| ul`, or adding `-c` to the `nroff` command.
Needs testing for old (OSX?) versions of nroff.
The terminal width magic that __fish_print_help learned doesn't help
when builtin_print_help runs it in a subshell. Instead, add an
undocumented --tty-width flag to __fish_print_help that's used to pass
the terminal width.
As a result of this rewrite, the output now:
* Expands to fit the terminal width, like `man` does
* Preprocesses the manpage with `tbl` just in case, since `man` does
this, even though I doubt any fish manpages use `tbl` formatting.
* Handle bold/underline with the `ul` command as it was designed for
instead of trying to fake it with `sed`.
* Compresses blank lines as `man` does with the default `less -is`
pager.
