Setting GH_COBRA allows access to Cobra's built-in implementation of generating man pages and markdown trees. This is useful for testing and comparing our overrides against Cobra's own logic.
It is good practice to wrap all dynamic content in `{% raw %}..{% endraw %}`
Liquid tags so that no syntax within can mistakenly get interpreted as
Liquid tags. Fixes rendering of `gh auth login` help page.
- "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
