VScode lexer: type name 'float16' is not highlited

[Alexey-T]

core.isph:

ISPC_BUILTINS_ATTRS ISPC_READONLY varying float16 __pseudo_gather32_half(varying int32, UIntMaskType);
ISPC_BUILTINS_ATTRS ISPC_READONLY varying float16 __pseudo_gather64_half(varying int64, UIntMaskType);