- Fix name of man pages for all but the toplevel command
- Set title of all man pages to "GitHub CLI manual"
- Include gh version information in man pages
- Clean up rendering of flags section
- List subcommands for every command
- "Examples" section now renders with syntax highlighting and doesn't
interpret curly braces as Liquid tags anymore
- Flags are now listed with nicer formatting than just being rendered to
a plain text block
- Flags are now listed above the "Examples" section
- The `--help` flag is no longer explicitly and repetitively being
listed as an inherited flag under every command
- Usage synopsis line is now rendered early in the documentation for a
command
- Every command that has subcommands now explicitly lists those
subcommands in its documentation
