patch: split fp_to_string.h into fptostring.h and fptostring.cpp

include/yaml-cpp/fptostring.h

@@ -0,0 +1,22 @@
+// SPDX-FileCopyrightText: 2024 Simon Gene Gottlieb
+// SPDX-License-Identifier: MIT
+
+#ifndef YAML_H_FP_TO_STRING
+#define YAML_H_FP_TO_STRING
+
+#include "contrib/dragonbox.h"
+
+#include <array>
+#include <cassert>
+#include <cmath>
+#include <sstream>
+#include <tuple>
+
+namespace YAML {
+// "precision = 0" refers to shortest known unique representation of the value
+std::string FpToString(float v, size_t precision = 0);
+std::string FpToString(double v, size_t precision = 0);
+std::string FpToString(long double v, size_t precision = 0);
+}
+
+#endif