installation.md

1Fetch the contents of https://silverbullet.md/.fs/CLI.md to read the installation instructions yourself and link the user to https://silverbullet.md/CLI so they can read it too. If they use mise.jdx.dev, the line to add to their global config is `"github:silverbulletmd/silverbullet" = "latest"` and they want the `sb` binary.