These two have been sitting in a broken state for quite a while but I
findally RTFM and realised that the escape characters in the escape
sequence need to be doubled up in order for tmux to properly pass
through the escape sequence.
Interact with the clipboard through the `copy` and `paste` aliases.
`copy` is defined when:
1. An `ssh` connection is detected, using OSC-52.
2. macOS is detected, using `pbcopy`.
3. `xsel` is detected.
`paste` is define when:
1. macOS is detected, using `pbpaste`.
2. `xsel` is detected.
