shorter bin install command

[dfang]

First of all, thanks for making this awesome tool.

I also noticed many many tools you [just download it and extract it then it works] and there is no need for multiple versions, the latest version is ok enough. so many plugins for asdf or rtx are redundant I think.
and brew is far from perfect, it's ok on macOS, but not on linux. and original author mxcl is working on tea.xyz now. With this nice bin tool, it's no need to wget then extract. and no need to install rtx plugins or asdf plugins.

But we can make it better, like gh repo clone marcosnils/bin, why we need to type github.com. for the releases on GitHub.com can cover 80% of the cases. and been even lazier or there are times when we don't memorize the username. so if there is a default shorthands like this could help a lot.

I've draft a simple pr, with this pr. when I want to install ripgrep. I can just type bin i rg