Add ELF dlopen note for libvkd3d-utils (hlsl->dxbc)

[madebr]

$ dlopen-notes.py libSDL3_shadercross.so.0
# libSDL3_shadercross.so.0
[
  {
    "feature": "dxbc",
    "description": "Create DXBC shaders from HLSL",
    "priority": "suggested",
    "soname": [
      "libvkd3d-utils.so.1"
    ]
  }
]