[wpimath] Templatize formatters (wpilibsuite#6535)

This is required for compatibility with libc++'s std::format.

Author: calcmogul

wpimath/src/main/native/include/frc/fmt/Eigen.h

@@ -18,11 +18,13 @@ template <typename Derived, typename CharT>
   requires std::derived_from<Derived, Eigen::DenseBase<Derived>> ||
            std::derived_from<Derived, Eigen::SparseCompressedBase<Derived>>
 struct fmt::formatter<Derived, CharT> {
-  constexpr auto parse(fmt::format_parse_context& ctx) {
+  template <typename ParseContext>
+  constexpr auto parse(ParseContext& ctx) {
     return m_underlying.parse(ctx);
   }
 
-  auto format(const Derived& mat, fmt::format_context& ctx) const {
+  template <typename FmtContext>
+  auto format(const Derived& mat, FmtContext& ctx) const {
     auto out = ctx.out();
 
     for (int row = 0; row < mat.rows(); ++row) {

wpimath/src/main/native/include/units/formatter.h

@@ -20,7 +20,8 @@
 template <typename Unit, typename CharT>
 struct fmt::formatter<Unit, CharT,
                       std::enable_if_t<units::traits::is_unit_t_v<Unit>>> {
-  constexpr auto parse(fmt::format_parse_context& ctx) {
+  template <typename ParseContext>
+  constexpr auto parse(ParseContext& ctx) {
     return m_underlying.parse(ctx);
   }
 
@@ -30,7 +31,8 @@ struct fmt::formatter<Unit, CharT,
    * @param obj Unit instance.
    * @param ctx Format string context.
    */
-  auto format(const Unit& obj, fmt::format_context& ctx) const {
+  template <typename FmtContext>
+  auto format(const Unit& obj, FmtContext& ctx) const {
     using Units = typename Unit::unit_type;
     using BaseUnits =
         units::unit<std::ratio<1>,