remove blank line between function and it's description

- remove the blank line between the declaration of the function and it's
  comment, leads to better IDE support when hovering over a function to see it's
  description
- remove the unnecessary duplication of the function name in the functions
  description
- slightly refactored code for lsb, msb in bitboard.h There are still a few
  things we can be improved later on, move the description of a function where
  it was declared (instead of implemented) and add descriptions to functions
  which are behind macros ifdefs

closes https://github.com/official-stockfish/Stockfish/pull/4840

No functional change

src/nnue/evaluate_nnue.cpp

@@ -233,7 +233,7 @@ static NnueEvalTrace trace_evaluate(const Position& pos) {
 constexpr std::string_view PieceToChar(" PNBRQK  pnbrqk");
 
 
-// format_cp_compact() converts a Value into (centi)pawns and writes it in a buffer.
+// Converts a Value into (centi)pawns and writes it in a buffer.
 // The buffer must have capacity for at least 5 chars.
 static void format_cp_compact(Value v, char* buffer) {
 
@@ -270,7 +270,7 @@ static void format_cp_compact(Value v, char* buffer) {
 }
 
 
-// format_cp_aligned_dot() converts a Value into pawns, always keeping two decimals
+// Converts a Value into pawns, always keeping two decimals
 static void format_cp_aligned_dot(Value v, std::stringstream& stream) {
 
     const double pawns = std::abs(0.01 * UCI::to_cp(v));
@@ -282,7 +282,7 @@ static void format_cp_aligned_dot(Value v, std::stringstream& stream) {
 }
 
 
-// trace() returns a string with the value of each piece on a board,
+// Returns a string with the value of each piece on a board,
 // and a table for (PSQT, Layers) values bucket by bucket.
 std::string trace(Position& pos) {
 

src/nnue/features/half_ka_v2_hm.cpp

@@ -50,7 +50,7 @@ void HalfKAv2_hm::append_active_indices(const Position& pos, IndexList& active)
 template void HalfKAv2_hm::append_active_indices<WHITE>(const Position& pos, IndexList& active);
 template void HalfKAv2_hm::append_active_indices<BLACK>(const Position& pos, IndexList& active);
 
-// append_changed_indices() : get a list of indices for recently changed features
+// Get a list of indices for recently changed features
 template<Color Perspective>
 void HalfKAv2_hm::append_changed_indices(Square            ksq,
                                          const DirtyPiece& dp,

src/nnue/nnue_common.h

@@ -85,7 +85,7 @@ constexpr IntType ceil_to_multiple(IntType n, IntType base) {
 }
 
 
-// read_little_endian() is our utility to read an integer (signed or unsigned, any size)
+// Utility to read an integer (signed or unsigned, any size)
 // from a stream in little-endian order. We swap the byte order after the read if
 // necessary to return a result with the byte ordering of the compiling machine.
 template<typename IntType>
@@ -110,7 +110,7 @@ inline IntType read_little_endian(std::istream& stream) {
 }
 
 
-// write_little_endian() is our utility to write an integer (signed or unsigned, any size)
+// Utility to write an integer (signed or unsigned, any size)
 // to a stream in little-endian order. We swap the byte order before the write if
 // necessary to always write in little endian order, independently of the byte
 // ordering of the compiling machine.
@@ -141,7 +141,7 @@ inline void write_little_endian(std::ostream& stream, IntType value) {
 }
 
 
-// read_little_endian(s, out, N) : read integers in bulk from a little indian stream.
+// Read integers in bulk from a little indian stream.
 // This reads N integers from stream s and put them in array out.
 template<typename IntType>
 inline void read_little_endian(std::istream& stream, IntType* out, std::size_t count) {
@@ -153,7 +153,7 @@ inline void read_little_endian(std::istream& stream, IntType* out, std::size_t c
 }
 
 
-// write_little_endian(s, values, N) : write integers in bulk to a little indian stream.
+// Write integers in bulk to a little indian stream.
 // This takes N integers from array values and writes them on stream s.
 template<typename IntType>
 inline void write_little_endian(std::ostream& stream, const IntType* values, std::size_t count) {
@@ -165,7 +165,7 @@ inline void write_little_endian(std::ostream& stream, const IntType* values, std
 }
 
 
-// read_leb_128(s, out, N) : read N signed integers from the stream s, putting them in
+// Read N signed integers from the stream s, putting them in
 // the array out. The stream is assumed to be compressed using the signed LEB128 format.
 // See https://en.wikipedia.org/wiki/LEB128 for a description of the compression scheme.
 template<typename IntType>
@@ -215,7 +215,7 @@ inline void read_leb_128(std::istream& stream, IntType* out, std::size_t count)
 }
 
 
-// write_leb_128(s, values, N) : write signed integers to a stream with LEB128 compression.
+// Write signed integers to a stream with LEB128 compression.
 // This takes N integers from array values, compress them with the LEB128 algorithm and
 // writes the result on the stream s.
 // See https://en.wikipedia.org/wiki/LEB128 for a description of the compression scheme.