message: [serde reflection] fix missing case in merge
  Closes:
  Approved by: bmwill
diff: @@ -323,10 +323,12 @@ impl FormatHolder for Format {
  | (Self::I16, Self::I16)
  | (Self::I32, Self::I32)
  | (Self::I64, Self::I64)
  + | (Self::I128, Self::I128)
  | (Self::U8, Self::U8)
  | (Self::U16, Self::U16)
  | (Self::U32, Self::U32)
  | (Self::U64, Self::U64)
  + | (Self::U128, Self::U128)
  | (Self::F32, Self::F32)
  | (Self::F64, Self::F64)
  | (Self::Char, Self::Char)
  