fmt: format must be const since fmt 10.0.0

Ensures this will work with recent fmt version (12.0.0).

Was not caught earlier since this code path is unused
unless someone actually uses the formatters.

Change-Id: Ida7a106cfae9ebf1a3f063308daccd1b7cb997b9

Author: lemirep

src/KDFoundation/formatters.h

@@ -26,7 +26,7 @@ struct KDFOUNDATION_API fmt::formatter<glm::vec3> {
     }
 
     template<typename FormatContext>
-    auto format(glm::vec3 const &v, FormatContext &ctx)
+    auto format(glm::vec3 const &v, FormatContext &ctx) const
     {
         return fmt::format_to(ctx.out(), "Vec3({:f}, {:f}, {:f})", v[0], v[1], v[2]);
     }
@@ -41,7 +41,7 @@ struct KDFOUNDATION_API fmt::formatter<glm::vec4> {
     }
 
     template<typename FormatContext>
-    auto format(glm::vec4 const &v, FormatContext &ctx)
+    auto format(glm::vec4 const &v, FormatContext &ctx) const
     {
         return fmt::format_to(ctx.out(), "Vec4({:f}, {:f}, {:f} {:f})", v[0], v[1], v[2], v[3]);
     }
@@ -56,7 +56,7 @@ struct KDFOUNDATION_API fmt::formatter<glm::quat> {
     }
 
     template<typename FormatContext>
-    auto format(glm::quat const &v, FormatContext &ctx)
+    auto format(glm::quat const &v, FormatContext &ctx) const
     {
         return fmt::format_to(ctx.out(), "Quat({:f}, {:f}, {:f} {:f})", v[0], v[1], v[2], v[3]);
     }
@@ -71,7 +71,7 @@ struct KDFOUNDATION_API fmt::formatter<glm::mat4> {
     }
 
     template<typename FormatContext>
-    auto format(glm::mat4 const &v, FormatContext &ctx)
+    auto format(glm::mat4 const &v, FormatContext &ctx) const
     {
         return fmt::format_to(ctx.out(), "Mat4({:f}, {:f}, {:f} {:f}\n     {:f}, {:f}, {:f} {:f}\n     {:f}, {:f}, {:f} {:f}\n     {:f}, {:f}, {:f} {:f})",
                               v[0][0], v[1][0], v[2][0], v[3][0],