[clap_mangen] possible values not shown in generated man page

[RubixDev]

Please complete the following tasks

• [X] I have searched the discussions
• [X] I have searched the open and rejected issues

Rust Version

rustc 1.61.0 (fe5b13d68 2022-05-18)

Clap Version

3.2.6

Minimal reproducible code

use clap::{Parser, CommandFactory};
use clap_mangen::Man;

#[derive(Parser)]
struct Cli {
    #[clap(long, action)]
    pub test: Option<bool>,
}

fn main() -> std::io::Result<()> {
    let mut cmd = Cli::command();

    cmd.write_long_help(&mut std::io::stderr())?;
    eprintln!("{}", "-".repeat(30));

    let man = Man::new(cmd);
    let mut buffer: Vec<u8> = Default::default();
    man.render(&mut buffer)?;
    println!("{}", String::from_utf8_lossy(&buffer));

    Ok(())
}

Steps to reproduce the bug with the above code

1. Add clap = { version = "3.2.6", features = ["derive"] } and clap_mangen = "0.1.9" to Cargo.toml
2. Run cargo run | man -P cat -l -

Actual Behaviour

The above example prints both the normal help message generated by clap and the man page generated by clap_mangen (example output is provided below). The man page does not mention the possible values (true and false) anywhere. The same is true for enums.

Expected Behaviour

The man page should mention the possible values just like the help message does ([possible values: true, false]).

Additional Context

Output of above example:

asd

USAGE:
    asd [OPTIONS]

OPTIONS:
    -h, --help
            Print help information

        --test <TEST>
            [possible values: true, false]
------------------------------
asd(1)      General Commands Manual      asd(1)

NAME
       asd

SYNOPSIS
       asd [-h|--help] [--test]

DESCRIPTION
OPTIONS
       -h, --help
              Print help information

       --test=TEST

                      asd                asd(1)

Debug Output

    Finished dev [unoptimized + debuginfo] target(s) in 0.02s
     Running `/home/silas/.cache/cargo/debug/asd`
[      clap::builder::command] 	Command::_build: name="asd"
[      clap::builder::command] 	Command::_propagate:asd
[      clap::builder::command] 	Command::_check_help_and_version: asd
[      clap::builder::command] 	Command::_check_help_and_version: Removing generated version
[      clap::builder::command] 	Command::_propagate_global_args:asd
[      clap::builder::command] 	Command::_derive_display_order:asd
[clap::builder::debug_asserts] 	Command::_debug_asserts
[clap::builder::debug_asserts] 	Arg::_debug_asserts:help
[clap::builder::debug_asserts] 	Arg::_debug_asserts:test
[clap::builder::debug_asserts] 	Command::_verify_positionals
[          clap::output::help] 	Help::new cmd=asd, use_long=true
[          clap::output::help] 	Help::write_help
[          clap::output::help] 	should_show_arg: use_long=true, arg=help
[          clap::output::help] 	Help::write_templated_help
[          clap::output::help] 	Help::write_before_help
[          clap::output::help] 	Help::write_bin_name
asd 

USAGE:
    [         clap::output::usage] 	Usage::create_usage_no_title
[         clap::output::usage] 	Usage::create_help_usage; incl_reqs=true
[         clap::output::usage] 	Usage::get_required_usage_from: incls=[], matcher=false, incl_last=false
[         clap::output::usage] 	Usage::get_required_usage_from: unrolled_reqs={}
[         clap::output::usage] 	Usage::get_required_usage_from: ret_val={}
[         clap::output::usage] 	Usage::needs_options_tag
[         clap::output::usage] 	Usage::needs_options_tag:iter: f=help
[         clap::output::usage] 	Usage::needs_options_tag:iter Option is built-in
[         clap::output::usage] 	Usage::needs_options_tag:iter: f=test
[      clap::builder::command] 	Command::groups_for_arg: id=test
[         clap::output::usage] 	Usage::needs_options_tag:iter: [OPTIONS] required
[         clap::output::usage] 	Usage::create_help_usage: usage=asd [OPTIONS]
asd [OPTIONS]

[          clap::output::help] 	Help::write_all_args
[          clap::output::help] 	should_show_arg: use_long=true, arg=help
[          clap::output::help] 	should_show_arg: use_long=true, arg=test
OPTIONS:
[          clap::output::help] 	Help::write_args OPTIONS
[          clap::output::help] 	should_show_arg: use_long=true, arg=help
[          clap::output::help] 	Help::write_args: arg="help" longest=6
[          clap::output::help] 	should_show_arg: use_long=true, arg=test
[          clap::output::help] 	Help::write_args: arg="test" longest=13
[          clap::output::help] 	should_show_arg: use_long=true, arg=help
[          clap::output::help] 	Help::spec_vals: a=--help
[          clap::output::help] 	Help::spec_vals: a=--help
[          clap::output::help] 	Help::short
    -h[          clap::output::help] 	Help::long
, --help[          clap::output::help] 	Help::val: arg=help
[          clap::output::help] 	Help::align_to_about: arg=help, next_line_help=true, longest=13
[          clap::output::help] 	Help::align_to_about: printing long help so skip alignment
[          clap::output::help] 	Help::help
[          clap::output::help] 	Help::help: Next Line...true

            [          clap::output::help] 	Help::help: Too long...
[          clap::output::help] 	No
Print help information

[          clap::output::help] 	Help::spec_vals: a=--test <TEST>
[          clap::output::help] 	Help::spec_vals: Found possible vals...[PossibleValue { name: "true", help: None, aliases: [], hide: false }, PossibleValue { name: "false", help: None, aliases: [], hide: false }]
[          clap::output::help] 	Help::short
        [          clap::output::help] 	Help::long
--test[          clap::output::help] 	Help::val: arg=test
 <TEST>[          clap::output::help] 	Help::align_to_about: arg=test, next_line_help=true, longest=13
[          clap::output::help] 	Help::align_to_about: printing long help so skip alignment
[          clap::output::help] 	Help::help
[          clap::output::help] 	Help::help: Next Line...true

            [          clap::output::help] 	Help::help: Too long...
[          clap::output::help] 	No
[possible values: true, false][          clap::output::help] 	Help::write_after_help

------------------------------
[      clap::builder::command] 	Command::_build: name="asd"
[      clap::builder::command] 	Command::_build: already built
[      clap::builder::command] 	Command::_build_bin_names
[         clap::output::usage] 	Usage::get_required_usage_from: incls=[], matcher=false, incl_last=true
[         clap::output::usage] 	Usage::get_required_usage_from: unrolled_reqs={}
[         clap::output::usage] 	Usage::get_required_usage_from: ret_val={}
.ie \n(.g .ds Aq \(aq
.el .ds Aq '
.TH asd 1  "asd " 
.SH NAME
asd
.SH SYNOPSIS
\fBasd\fR [\fB\-h\fR|\fB\-\-help\fR] [\fB\-\-test\fR] 
.SH DESCRIPTION
.SH OPTIONS
.TP
\fB\-h\fR, \fB\-\-help\fR
Print help information
.TP
\fB\-\-test\fR=\fITEST\fR

[epage]

Huh, we have #3360 for improving possible values but not an issue for tracking showing them in the first place.

[Calder-Ty]

I wouldn't mind working on this if it's not being handled already

[epage]

Go for it!