dxcapi.h is missing #defines for 2 DXC_PART_ values ('S','F','I','0' and 'P','S','V','0')

Description
While enumerating parts in a DXIL container using the reflection data interface, I noticed that there were some unknown values being returned. Looks like the dxcapi.h is missing them

The FOURCC values missing are:
'S','F','I','0' and 'P','S','V','0'

Steps to Reproduce

// dxapi.h header

#define DXC_FOURCC(ch0, ch1, ch2, ch3) (                     \
  (UINT32)(UINT8)(ch0)        | (UINT32)(UINT8)(ch1) << 8  | \
  (UINT32)(UINT8)(ch2) << 16  | (UINT32)(UINT8)(ch3) << 24   \
  )
#define DXC_PART_PDB                      DXC_FOURCC('I', 'L', 'D', 'B')
#define DXC_PART_PDB_NAME                 DXC_FOURCC('I', 'L', 'D', 'N')
#define DXC_PART_PRIVATE_DATA             DXC_FOURCC('P', 'R', 'I', 'V')
#define DXC_PART_ROOT_SIGNATURE           DXC_FOURCC('R', 'T', 'S', '0')
#define DXC_PART_DXIL                     DXC_FOURCC('D', 'X', 'I', 'L')
#define DXC_PART_REFLECTION_DATA          DXC_FOURCC('S', 'T', 'A', 'T')
#define DXC_PART_SHADER_HASH              DXC_FOURCC('H', 'A', 'S', 'H')
#define DXC_PART_INPUT_SIGNATURE          DXC_FOURCC('I', 'S', 'G', '1')
#define DXC_PART_OUTPUT_SIGNATURE         DXC_FOURCC('O', 'S', 'G', '1')
#define DXC_PART_PATCH_CONSTANT_SIGNATURE DXC_FOURCC('P', 'S', 'G', '1')

void FourCCToString(uint32_t value)
{
    uint8_t* values = reinterpret_cast<uint8_t*>(&value);
    for (size_t i = 0; i < 4; ++i)
    {
        std::cout << "'" << values[i] << "' ";
    }
    std::cout << "\n";
}

const char* DxcPartKindToString(uint32_t kind)
{
    switch (kind)
    {
    case DXC_PART_PDB:
        return "DXC_PART_PDB";
    case DXC_PART_PDB_NAME:
        return "DXC_PART_PDB_NAME";
    case DXC_PART_PRIVATE_DATA:
        return "DXC_PART_PRIVATE_DATA";
    case DXC_PART_ROOT_SIGNATURE:
        return "DXC_PART_ROOT_SIGNATURE";
    case DXC_PART_DXIL:
        return "DXC_PART_DXIL";
    case DXC_PART_REFLECTION_DATA:
        return "DXC_PART_REFLECTION_DATA";
    case DXC_PART_SHADER_HASH:
        return "DXC_PART_SHADER_HASH";
    case DXC_PART_INPUT_SIGNATURE:
        return "DXC_PART_INPUT_SIGNATURE";
    case DXC_PART_OUTPUT_SIGNATURE:
        return "DXC_PART_OUTPUT_SIGNATURE";
    case DXC_PART_PATCH_CONSTANT_SIGNATURE:
        return "DXC_PART_PATCH_CONSTANT_SIGNATURE";
    default:
        FourCCToString(kind); // Print unknown kind value
        return "UNKNOWN";
    }
}


void PrintSupportedDXILContainerParts(IDxcContainerReflection* containerReflection)
{
    uint32_t numParts = 0;
    check_hresult(containerReflection->GetPartCount(&numParts));
    std::cout << numParts << " total parts found in DXIL container reflection data\n";
    for (uint32_t i = 0; i < numParts; ++i)
    {
        uint32_t partKind = 0;
        check_hresult(containerReflection->GetPartKind(i, &partKind));
        std::cout << DxcPartKindToString(partKind) << " found in DIXL container reflection data\n";
    }
}

Example of output

8 total parts found in DXIL container reflection data
'S' 'F' 'I' '0'
UNKNOWN found in DIXL container reflection data
DXC_PART_INPUT_SIGNATURE found in DIXL container reflection data
DXC_PART_OUTPUT_SIGNATURE found in DIXL container reflection data
'P' 'S' 'V' '0'
UNKNOWN found in DIXL container reflection data
DXC_PART_REFLECTION_DATA found in DIXL container reflection data
DXC_PART_PDB_NAME found in DIXL container reflection data
DXC_PART_SHADER_HASH found in DIXL container reflection data
DXC_PART_DXIL found in DIXL container reflection data

Environment

• DXC version dxcompiler.dll: 1.8 - 1.8.2403.37 (11e1318c3); dxil.dll: 1.8(101.8.2403.24)
• Host Operating System Windows 11

Start in dxcapi.h beside the existing DXC_PART definitions and compare the reflected part kinds with the two FOURCC values reported in the issue. Add the corresponding named definitions and verify that SF I0 and PSV0 are recognized rather than reported as unknown.