Say in the options table that a proven link resets the backoff

maxDelay bounds the wait and sets the bar a link must clear, and only the
first was documented, so tuning it up quietly lengthened every recovery.

The unreadable PDU the tests write is one named constant now.

test/session.test.ts

@@ -1374,7 +1374,6 @@ describe('application hooks that throw or reject', () => {
 	});
 
 	test('keeps backing off when every link dies as soon as it comes up', async t => {
-		// A stream we cannot read is found after the bind, so a bind alone must not prove the link.
 		const clock = { now: 0 };
 		const delays: number[] = [];
 		const noop = (): void => undefined;