Enabled Native16Bit requirement for Vulkan, which sets a precedent for other graphics APIs to use this as well

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/ASR/Shaders/ffxm_fsr2_common.cginc

@@ -3,6 +3,13 @@
 #pragma warning(disable: 3205)      // Conversion from larger type to smaller, possible loss of data
 #pragma warning(disable: 3556)      // Integer divides might be much slower, try using uints if possible
 
+// Doesn't work for:
+// - DX11: forces use of DXC which is not supported
+// - XB1: native FP16 seems to be unsupported
+#if defined(SHADER_API_VULKAN)
+#pragma require Native16Bit
+#endif
+
 // If these keywords are set by Unity, redefine them to have a truthy value
 #ifdef FFXM_FSR2_OPTION_SHADER_OPT_PERFORMANCE
 #undef FFXM_FSR2_OPTION_SHADER_OPT_PERFORMANCE