avoid lambda trailing return type (GCC 10.2 fix)

PiperOrigin-RevId: 469444451

Author: jan-wassenberg

hwy/ops/x86_128-inl.h

@@ -5654,8 +5654,7 @@ HWY_API Vec128<double, N> ConvertTo(HWY_MAYBE_UNUSED Simd<double, N, 0> dd,
   const VU v_lo = And(v, msk_lo);
   const VU v_hi = ShiftRight<32>(v);
 
-  auto uint64_to_double128_fast = [&dd](VU w) HWY_ATTR
-  {
+  auto uint64_to_double128_fast = [&dd](VU w) HWY_ATTR {
     w = Or(w, VU{detail::BitCastToInteger(Set(dd, 0x0010000000000000).raw)});
     return BitCast(dd, w) - Set(dd, 0x0010000000000000);
   };

hwy/ops/x86_256-inl.h

@@ -4244,8 +4244,7 @@ HWY_API Vec256<double> ConvertTo(HWY_MAYBE_UNUSED Full256<double> dd,
   const VU v_lo = And(v, msk_lo);
   const VU v_hi = ShiftRight<32>(v);
 
-  auto uint64_to_double256_fast = [&dd](Vec256<uint64_t> w)
-                                      HWY_ATTR -> Vec256<double> {
+  auto uint64_to_double256_fast = [&dd](Vec256<uint64_t> w) HWY_ATTR {
     w = Or(w, Vec256<uint64_t>{
                   detail::BitCastToInteger(Set(dd, 0x0010000000000000).raw)});
     return BitCast(dd, w) - Set(dd, 0x0010000000000000);