Updates how tmux does numbering.
Updates how tmux does numbering.

Starts numbering for panes and windows at 1.

This comes from
[this](https://lucasfcosta.com/2019/02/10/terminal-guide-2019.html) blog
post, and seems like it may have good ergonomics because `0` is sort of
far/harder to get to.

tmr08c/dotfiles,tmr08c/dotfiles