Add support for OSC 52

[halcyon]

OSC 52 control code can be used to copy text into the clipboard.
tmux has native support for the OSC 52 sequence. See man tmux https://linux.die.net/man/1/tmux under the set-clipboard setting.

It looks like this feature has been implemented in Gnome Terminal - https://gitlab.gnome.org/GNOME/vte/-/issues/2495

Context

If QTerminal could support OSC 52 it would remove the reliance on xclip or xsel and copying in tmux would work regardless of ssh tunnels. For many years I've utilized X11 forwarding via SSH to provide clipboard access to my editor running on a remote system in the terminal. Now that I've switched to Wayland, this no longer seems to be a viable option.

[halcyon]

This seems to be a popular request. It seems like there are a lot of terminals and terminal-based tools implementing this.

This repository looks a little bit out of date, but may be helpful with implementation. It also lists a number of terminals that have implemented support for OSC 52: https://github.com/ojroques/vim-oscyank/tree/main