QoL: improve gcode marker (#11881)

QoL: Improve gcode marker

src/libslic3r/GCode/GCodeProcessor.cpp

@@ -5412,6 +5412,7 @@ void GCodeProcessor::store_move_vertex(EMoveType type, EMovePathType path_type,
         m_fan_speed,
         m_extruder_temps[filament_id],
         { 0.0f, 0.0f }, // time
+        static_cast<float>(m_layer_id), //layer_duration: set later
         std::max<unsigned int>(1, m_layer_id) - 1,
         internal_only,
         m_object_label_id,

src/libslic3r/GCode/GCodeProcessor.hpp

@@ -185,6 +185,7 @@ class Print;
             float fan_speed{ 0.0f }; // percentage
             float temperature{ 0.0f }; // Celsius degrees
             std::array<float, static_cast<size_t>(PrintEstimatedStatistics::ETimeMode::Count)> time{ 0.0f, 0.0f }; // s
+            float layer_duration{ 0.0f }; // s
             unsigned int layer_id{ 0 };
             bool internal_only{ false };