Add necessary includes

Insert a few missing include statements.

Author: mmoult

src/values/primitive.cxx

@@ -9,6 +9,7 @@ module;
 #include <cmath>
 #include <cstdint>  // for uint32_t and int32_t
 #include <limits>
+#include <sstream>
 #include <stdexcept>
 
 #include "type.hpp"

src/values/raytrace/shader-binding-table.cxx

@@ -4,6 +4,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 module;
+#include <sstream>
 #include <string>
 #include <vector>
 

src/values/type.cpp

@@ -6,6 +6,7 @@
 #include "type.hpp"
 
 #include <cassert>
+#include <sstream>
 #include <stdexcept>
 #include <vector>