Add #partial [Enum]Type{...} support to check for missing enumerated array fields

core/compress/gzip/gzip.odin

@@ -67,6 +67,7 @@ OS :: enum u8 {
 	Unknown      = 255,
 }
 OS_Name :: #sparse[OS]string{
+	._Unknown     = "",
 	.FAT          = "FAT",
 	.Amiga        = "Amiga",
 	.VMS          = "VMS/OpenVMS",

core/math/big/common.odin

@@ -182,6 +182,7 @@ Error_String :: #sparse[Error]string{
 	.Max_Iterations_Reached  = "Max iterations reached",
 	.Buffer_Overflow         = "Buffer overflow",
 	.Integer_Overflow        = "Integer overflow",
+	.Integer_Underflow       = "Integer underflow",
 
 	.Division_by_Zero        = "Division by zero",
 	.Math_Domain_Error       = "Math domain error",