This adds a new annotation to commands that are known to be frequently
used, and allows setting a custom weight/order for these commands to
influence in what order they appear in the --help output.
I'm not entirely happy with the implementation (we could at least use
some helpers for this, and/or make it more generic to group commands
in output), but it could be a start.
For now, limiting this to only be used for the top-level --help, but
we can expand this to subcommands as well if we think it makes sense
to highlight "common" / "commonly used" commands.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>