Lack of clarity in --help relative to README.md

The line in --help for install can be confusing it doesn't match what is in the readme. The install line says `install Adds a new tool using Rokit and installs it` which doesn't clarify that to install all the package you do not specify any arguments and instead just call `rokit install` in the project directory and it installs each tool. This differs to on the readme where it says `rokit install - Installs all project-specific tools.` which was very clear to me and helped fix the problem I was having. Thank you for making this tool, it is very helpful!