Install command for MacOS does not work

Macbook Pro 2018 running Sonoma 14.1.1 gives:

```
$ brew install --cask font-jetbrains-mono

Warning: Cask 'font-jetbrains-mono' is unavailable: No Cask with this name exists.
==> Searching for similarly named casks...
Error: No casks found for font-jetbrains-mono.
[ble: exit 1]
```