Removing signup headers, making clear signup is on-site.
'''Note: Lightning talk signups will happen in person at the Conference — please do not sign up until thenconference.'''== Day 1 - March 15, 2023 ==* Talk 1== Day 2 - March 16, 2023 ==* Talk 2== Day 3 - March 17, 2023 ==* Talk 3
