message: Move Traits struct and Create method out of --cpp-static-reflection.
diff: @@ -2159,6 +2159,7 @@ class CppGenerator : public BaseGenerator {
  // We have a table and not a struct.
  code_ += " static auto constexpr Create = Create{{STRUCT_NAME}};";
  }
  + if (opts_.cpp_static_reflection) {
  code_ += " static constexpr auto name = \"{{STRUCT_NAME}}\";";
  code_ +=
  " static constexpr auto fully_qualified_name = "
  @@ -2166,6 +2167,7 @@ class CppGenerator : public BaseGenerator {
  GenFieldNames(struct_def);
  GenFieldTypeHelper(struct_def);
  GenFieldsNumber(struct_def);
  + }
  code_ += "};";
  code_ += "";
  }
  @@ -2227,7 +2229,7 @@ class CppGenerator : public BaseGenerator {
  code_ += " typedef {{NATIVE_NAME}} NativeTableType;";
  }
  code_ += " typedef {{STRUCT_NAME}}Builder Builder;";
  - if (opts_.cpp_static_reflection) { code_ += " struct Traits;"; }
  + if (opts_.g_cpp_std >= cpp::CPP_STD_17) { code_ += " struct Traits;"; }
  if (opts_.mini_reflect != IDLOptions::kNone) {
  code_ +=
  " static const flatbuffers::TypeTable *MiniReflectTypeTable() {";
  @@ -2519,7 +2521,7 @@ class CppGenerator : public BaseGenerator {
  // Definition for type traits for this table type. This allows querying var-
  // ious compile-time traits of the table.
  - if (opts_.cpp_static_reflection) { GenTraitsStruct(struct_def); }
  + if (opts_.g_cpp_std >= cpp::CPP_STD_17) { GenTraitsStruct(struct_def); }
  // Generate a CreateXDirect function with vector types as parameters
  if (opts_.cpp_direct_copy && has_string_or_vector_fields) {
  @@ -3293,7 +3295,7 @@ class CppGenerator : public BaseGenerator {
  code_ += "";
  code_ += " public:";
  - if (opts_.cpp_static_reflection) { code_ += " struct Traits;"; }
  + if (opts_.g_cpp_std >= cpp::CPP_STD_17) { code_ += " struct Traits;"; }
  // Make TypeTable accessible via the generated struct.
  if (opts_.mini_reflect != IDLOptions::kNone) {
  @@ -3392,7 +3394,7 @@ class CppGenerator : public BaseGenerator {
  // Definition for type traits for this table type. This allows querying var-
  // ious compile-time traits of the table.
  - if (opts_.cpp_static_reflection) { GenTraitsStruct(struct_def); }
  + if (opts_.g_cpp_std >= cpp::CPP_STD_17) { GenTraitsStruct(struct_def); }
  }
  // Set up the correct namespace. Only open a namespace if the existing one is
  