Cleanup usage documentation for chkconfig

Usage documentation for the `chkconfig`, `config`, and `config generate` subcommands contained some unescaped backticks. Those unescaped characters were preventing the text within them from being visible.

In addition, I added explicit references to the configuration files (`{{package_name}}.conf` and `advanced.config`) inspected by the subcommands.

This pull request aims to resolve https://github.com/basho/node_package/issues/147.

/cc @macintux