docs: Fix "Getting Started" code snippet (#1519) [skip ci]
docs: Fix "Getting Started" code snippet (#1519) [skip ci]

`$_` retrieves the last argument of the previous command.
`!$` retrieves the last argument of previous command in the shell
history.
https://unix.stackexchange.com/a/219627
sebmck/lerna,evocateur/lerna,lerna/lerna,evocateur/lerna,lerna/lerna,lerna/lerna,kittens/lerna