feat: add man subcommand to generate man pages with clap_mangen

[Rahul-pamula]

Summary
This PR resolves the issue by adding a plainly documented weaveffi man --out <dir> subcommand to generate roff man pages using clap_mangen.

Implementation Details

• Automatically generates the top-level weaveffi.1 man page and one man page for every existing subcommand (e.g., weaveffi-generate.1, weaveffi-doctor.1).
• Dynamically iterates over the clap::Command subcommands using .get_subcommands() and forces proper name formatting in the generated roff file.
• Respects the global --quiet flag (informational logging is suppressed when passed).
• Added clap_mangen = "0.2" to crates/weaveffi-cli/Cargo.toml.
• Added an integration test man_generation matching the style of the existing completions_bash test to assert the command executes properly and generates the correct files.
• Mentioned the new command in the CLI reference table of README.md and added a Generating Man Pages section to docs/src/getting-started.md.

Testing

• All tests pass locally via cargo test -p weaveffi-cli.
• Verified man ./man/weaveffi.1 successfully renders without any roff parser errors.
• Verified cargo fmt --check and cargo clippy -D warnings pass.

Closes: #40

[owenthcarey]

Thanks for the contribution, this is a really thorough first PR! The tests, docs, and --quiet handling are all exactly what the issue asked for, and CI is green across the board.

I'm requesting two small changes before merging, both inline below with suggestions you can apply directly. Once those are in, I'll squash merge. Thanks again!

[owenthcarey]

clap_mangen ships a helper that does all of this for you: clap_mangen::generate_to renders the top-level page plus one page per subcommand, names them weaveffi-<sub>.1 via clap's display names, skips the help subcommand, and recurses into nested subcommands if we ever add any.

That also gets rid of the .leak() workaround, which permanently leaks each formatted name (clap's Command::name needs a 'static string when the string feature is off, which is why you needed it, but we'd rather not have that pattern in the codebase).

Your existing man_generation test passes unchanged with this version:

Suggested change

	fn cmd_man(out: &str, quiet: bool) -> Result<()> {
	let out_dir = std::path::PathBuf::from(out);
	std::fs::create_dir_all(&out_dir)
	.into_diagnostic()
	.wrap_err_with(|| format!("failed to create directory: {out}"))?;
	let mut cmd = Cli::command();
	cmd.build();
	let mut buffer = Vec::new();
	clap_mangen::Man::new(cmd.clone())
	.render(&mut buffer)
	.into_diagnostic()
	.wrap_err("failed to render man page for weaveffi")?;
	std::fs::write(out_dir.join("weaveffi.1"), buffer)
	.into_diagnostic()
	.wrap_err("failed to write weaveffi.1")?;
	for sub in cmd.get_subcommands() {
	let sub_name = sub.get_name();
	if sub_name == "help" {
	continue;
	}
	let sub_cmd = sub.clone().name(&*format!("weaveffi-{sub_name}").leak());
	let mut sub_buffer = Vec::new();
	clap_mangen::Man::new(sub_cmd)
	.render(&mut sub_buffer)
	.into_diagnostic()
	.wrap_err_with(|| format!("failed to render man page for weaveffi-{sub_name}"))?;
	std::fs::write(out_dir.join(format!("weaveffi-{sub_name}.1")), sub_buffer)
	.into_diagnostic()
	.wrap_err_with(|| format!("failed to write weaveffi-{sub_name}.1"))?;
	}
	if !quiet {
	println!("Man pages written to {}", out_dir.display());
	}
	Ok(())
	}
	fn cmd_man(out: &str, quiet: bool) -> Result<()> {
	let out_dir = std::path::PathBuf::from(out);
	std::fs::create_dir_all(&out_dir)
	.into_diagnostic()
	.wrap_err_with(|| format!("failed to create directory: {out}"))?;
	clap_mangen::generate_to(Cli::command(), &out_dir)
	.into_diagnostic()
	.wrap_err("failed to generate man pages")?;
	if !quiet {
	println!("Man pages written to {}", out_dir.display());
	}
	Ok(())
	}

[owenthcarey]

All dependencies in this workspace are pinned in [workspace.dependencies] in the root Cargo.toml (its siblings clap and clap_complete are there already). Could you add clap_mangen = "0.2" there and reference it here with:

Suggested change

	clap_mangen = "0.2"
	clap_mangen = { workspace = true }