Example: always create a shpool session when using SSH

@thiswillbeyourgithub shared an example showing how to create a new shpool session on ssh login:

## directly checks if it should start a tmux session to avoir running the entire zshrc twice
if [[ "$ZSH_ARGZERO" == *"zsh" ]]  # don't create a shpool is an argument was given to zsh
then
    # create a new shpool session
    $(printenv | grep -q '^SHPOOL_SESSION_NAME=') || {  # if we're not already in a shpool session
        {
            sessions=$(shpool list | tail -n +2 | cut -f1)
            for letter in {a..z}  # sessions are named a through z to be easy to type on termux, as shpool has no autocomplete
            do
                $(echo "$sessions" | grep -q "$letter") || {
                    # notify-send "Creating shpool session $letter"
                    shpool attach "$letter" || notify-send "Error creating shpool session"
                    break  # we could logout here too
                }
            done
        } || { notify-send -u critical "Error creating shpool session" ; echo "Error creating shpool session" }
    }
    $(printenv | grep -q '^SHPOOL_SESSION_NAME=') && {
        echo "Using shpool session $SHPOOL_SESSION_NAME"
    }
fi