Re: reorganize "Shared Memory and LWLocks" section of docs

Hi,

Thanks for the updated patch.

> > I see what you mean, but I don't think the problem is the word "each."  I
> > think the problem is the use of passive voice.  What do you think about
> > something like
> >
> >       Each backend will execute the registered shmem_startup_hook shortly
> >       after it attaches to shared memory.

That's much better, thanks.

I think the patch could use another pair of eyes, ideally from a
native English speaker. But if no one will express any objections for
a while I suggest merging it.

-- 
Best regards,
Aleksander Alekseev