Show Desktop Notification (OSC 9)

Show a desktop notification with title t.

To avoid conflicting with the ConEmu extensions, which also use OSC 9 due to historical happenstance, the title should not begin with a number and then a semicolon (;). In practice a collision of this kind should be rare. Ghostty's parser will silently convert any invalid ConEmu sequence to a OSC 9 sequence, though this behavior should not be relied upon.

Originated from iTerm since before 2010.