Minor code improvements

- Remove / add empty lines
- fix the `ttcapture` comment
- remove the `bonus` variable for `ttMoveHistory`
- remove unnecessary parentheses / brackets
- refactor the movepick good quiet stage
- rename `endMoves` to `endCur`, as the previous name suggests that it points to the end of all generated moves, which it does not.

closes https://github.com/official-stockfish/Stockfish/pull/6089

No functional change.

Co-Authored-By: xu-shawn <50402888+xu-shawn@users.noreply.github.com>

src/movepick.cpp

@@ -173,7 +173,7 @@ void MovePicker::score() {
             if (KNIGHT <= pt && pt <= QUEEN)
             {
                 static constexpr int bonus[QUEEN + 1] = {0, 0, 144, 144, 256, 517};
-                int v = (threatByLesser[pt] & to ? -95 : 100 * bool(threatByLesser[pt] & from));
+                int v = threatByLesser[pt] & to ? -95 : 100 * bool(threatByLesser[pt] & from);
                 m.value += bonus[pt] * v;
             }
 
@@ -200,7 +200,7 @@ void MovePicker::score() {
 template<typename Pred>
 Move MovePicker::select(Pred filter) {
 
-    for (; cur < endMoves; ++cur)
+    for (; cur < endCur; ++cur)
         if (*cur != ttMove && filter())
             return *cur++;
 
@@ -227,10 +227,10 @@ top:
     case PROBCUT_INIT :
     case QCAPTURE_INIT :
         cur = endBadCaptures = moves;
-        endMoves             = generate<CAPTURES>(pos, cur);
+        endCur               = generate<CAPTURES>(pos, cur);
 
         score<CAPTURES>();
-        partial_insertion_sort(cur, endMoves, std::numeric_limits<int>::min());
+        partial_insertion_sort(cur, endCur, std::numeric_limits<int>::min());
         ++stage;
         goto top;
 
@@ -250,10 +250,10 @@ top:
         if (!skipQuiets)
         {
             cur = endBadQuiets = endBadCaptures;
-            endMoves           = generate<QUIETS>(pos, cur);
+            endCur             = generate<QUIETS>(pos, cur);
 
             score<QUIETS>();
-            partial_insertion_sort(cur, endMoves, -3560 * depth);
+            partial_insertion_sort(cur, endCur, -3560 * depth);
         }
 
         ++stage;
@@ -261,13 +261,16 @@ top:
 
     case GOOD_QUIET :
         if (!skipQuiets && select([&]() {
-                return cur->value > -14000 ? true : (*endBadQuiets++ = *cur, false);
+                if (cur->value > -14000)
+                    return true;
+                *endBadQuiets++ = *cur;
+                return false;
             }))
             return *(cur - 1);
 
         // Prepare the pointers to loop over the bad captures
-        cur      = moves;
-        endMoves = endBadCaptures;
+        cur    = moves;
+        endCur = endBadCaptures;
 
         ++stage;
         [[fallthrough]];
@@ -277,8 +280,8 @@ top:
             return *(cur - 1);
 
         // Prepare the pointers to loop over the bad quiets
-        cur      = endBadCaptures;
-        endMoves = endBadQuiets;
+        cur    = endBadCaptures;
+        endCur = endBadQuiets;
 
         ++stage;
         [[fallthrough]];
@@ -290,11 +293,11 @@ top:
         return Move::none();
 
     case EVASION_INIT :
-        cur      = moves;
-        endMoves = generate<EVASIONS>(pos, cur);
+        cur    = moves;
+        endCur = generate<EVASIONS>(pos, cur);
 
         score<EVASIONS>();
-        partial_insertion_sort(cur, endMoves, std::numeric_limits<int>::min());
+        partial_insertion_sort(cur, endCur, std::numeric_limits<int>::min());
         ++stage;
         [[fallthrough]];
 
@@ -317,7 +320,7 @@ bool MovePicker::can_move_king_or_pawn() {
     // SEE negative captures shouldn't be returned in GOOD_CAPTURE stage
     assert(stage > GOOD_CAPTURE && stage != EVASION_INIT);
 
-    for (ExtMove* m = moves; m < endMoves; ++m)
+    for (ExtMove* m = moves; m < endCur; ++m)
     {
         PieceType movedPieceType = type_of(pos.moved_piece(*m));
         if ((movedPieceType == PAWN || movedPieceType == KING) && pos.legal(*m))