format_to and format_to_n failes with option '=' on 'f'

[ck3d]

Following code example shows, that format_to and format_to_n fails to format floats while using option '='. (fmtlib version 5.0.0)

#include <fmt/format.h>
#include <array>
#include <cassert>
#include <string>

using namespace fmt;

int main() {
  std::array<char, 6> buffer;
  auto format = "{0:0=+6.2f}";

  // passing case
  assert(fmt::format(format, -3.8) == "-03.80");

  // failing cases
  assert(fmt::format_to(buffer.begin(), format, 3.21) == buffer.end()); // got buffer.end() -1
  assert(std::string(buffer.data(), buffer.size()) == "+03.21"); // got "03.21 "

  assert(fmt::format_to_n(buffer.begin(), buffer.size(), format, -1.23).size ==
         buffer.size()); // got 5 instead of 6

  assert(std::string(buffer.data(), buffer.size()) == "-01.23"); // got "01.23 "
}

[vitaut]

Fixed in fc6e0fe & 1b8a7f8, thanks a lot for reporting!