docs/vm: hwpoison.rst: Fix quote formatting

This patchkit implements the necessary infrastructure in the VM.

To quote the overview comment:

 * High level machine check handler. Handles pages reported by the

 * hardware as being corrupted usually due to a 2bit ECC memory or cache

 * failure.

 *

 * This focusses on pages detected as corrupted in the background.

 * When the current CPU tries to consume corruption the currently

 * running process can just be killed directly instead. This implies

 * that if the error cannot be handled for some reason it's safe to

 * just ignore it because no corruption has been consumed yet. Instead

 * when that happens another machine check will happen.

 *

 * Handles page cache pages in various states. The tricky part

 * here is that we can access any page asynchronous to other VM

 * users, because memory failures could happen anytime and anywhere,

 * possibly violating some of their assumptions. This is why this code

 * has to be extremely careful. Generally it tries to use normal locking

 * rules, as in get the standard locks, even if that means the

 * error handling takes potentially a long time.

 *

 * Some of the operations here are somewhat inefficient and have non

 * linear algorithmic complexity, because the data structures have not

 * been optimized for this case. This is in particular the case

 * for the mapping from a vma to a process. Since this case is expected

 * to be rare we hope we can get away with this.

To quote the overview comment::

	High level machine check handler. Handles pages reported by the

	hardware as being corrupted usually due to a 2bit ECC memory or cache

	failure.

	This focusses on pages detected as corrupted in the background.

	When the current CPU tries to consume corruption the currently

	running process can just be killed directly instead. This implies

	that if the error cannot be handled for some reason it's safe to

	just ignore it because no corruption has been consumed yet. Instead

	when that happens another machine check will happen.

	Handles page cache pages in various states. The tricky part

	here is that we can access any page asynchronous to other VM

	users, because memory failures could happen anytime and anywhere,

	possibly violating some of their assumptions. This is why this code

	has to be extremely careful. Generally it tries to use normal locking

	rules, as in get the standard locks, even if that means the

	error handling takes potentially a long time.

	Some of the operations here are somewhat inefficient and have non

	linear algorithmic complexity, because the data structures have not

	been optimized for this case. This is in particular the case

	for the mapping from a vma to a process. Since this case is expected

	to be rare we hope we can get away with this.

The code consists of a the high level handler in mm/memory-failure.c,

a new page poison bit and various checks in the VM to handle poisoned