Reformat and rename hash_after_move()

Align to standard coding style and properly use
enum types. Rename while there.

No functional change.
This is what has been tested. Any change should be retested.

On Sat, Oct 4, 2014 at 8:26 AM, hwiechers <notifications@github.com> wrote:

> In src/search.cpp:
>
> > @@ -788,8 +788,8 @@ namespace {
> >            }
> >        }
> >
> > -      // Speculative prefetch
> > -      prefetch((char*)TT.first_entry(pos.hash_after_move(move)));
> > +      // Speculative prefetch as early as possible
>
> Is it really as early as possible? All you need for the prefetch is the
> pos and move, right?
> So couldn't you move it right to the start of Step 11 if you wanted to be
> even more speculative?
>
> —
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> <https://github.com/official-stockfish/Stockfish/pull/65/files#r18427895>.
>