docs: add error handlers to examples, and improve error event description

[dyc3]

• docs: add minimal error handlers to examples
• docs: indicate that failing to handle an error event will crash the process

[lpinca]

There were unrelated changes, some missing handlers, and some nits to fix, so I went ahead and pushed b82682a. I did not change the 'error' event description because crashing on unhandled 'error' events is standard Node.js behavior.

Thank you anyway.