bpo-36794: Document that Lock.acquire is fair. (GH-13082)

bpo-36794: Document that Lock.acquire is fair. (GH-13082) · python/cpython@34f4f5e

Original file line number	Diff line number	Diff line change
`@@ -66,6 +66,13 @@ Lock`
`66`	`66`	`This method waits until the lock is unlocked, sets it to`
`67`	`67`	locked and returns ``True``.
`68`	`68`
	`69`	+ When more than one coroutine is blocked in :meth:`acquire`
	`70`	`+ waiting for the lock to be unlocked, only one coroutine`
	`71`	`+ eventually proceeds.`
	`72`	`+`
	`73`	`+ Acquiring a lock is fair: the coroutine that proceeds will be`
	`74`	`+ the first coroutine that started waiting on the lock.`
	`75`	`+`
`69`	`76`	`.. method:: release()`
`70`	`77`
`71`	`78`	`Release the lock.`