Readded item_syntesis.hpp and item_syntesis.cpp to map-server filter

src/map/map-server.vcxproj.filters

@@ -152,6 +152,9 @@
     <ClInclude Include="item_upgrade.hpp">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="item_synthesis.hpp">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="achievement.cpp">
@@ -280,5 +283,8 @@
     <ClCompile Include="item_upgrade.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="item_synthesis.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
-</Project>
+</Project>