gguf: add custom Q_K_XL quants (#1452)

As reported by @unslothai , these quant types are custom (not officially
exist in llama.cpp). Adding these to the list so it will be recognized
via registry API

After this PR is merged, we will also push the change to main code base
(aka moon-landing)

Author: ngxson

packages/tasks/src/gguf.ts

@@ -40,6 +40,15 @@ export enum GGMLFileQuantizationType {
 	Q4_0_8_8 = 35,
 	TQ1_0 = 36,
 	TQ2_0 = 37,
+
+	// custom quants used by unsloth
+	// they are not officially a scheme enum value in GGUF, but only here for naming
+	Q2_K_XL = 1000,
+	Q3_K_XL = 1001,
+	Q4_K_XL = 1002,
+	Q5_K_XL = 1003,
+	Q6_K_XL = 1004,
+	Q8_K_XL = 1005,
 }
 
 const ggufQuants = Object.values(GGMLFileQuantizationType).filter((v): v is string => typeof v === "string");
@@ -58,32 +67,37 @@ export const GGUF_QUANT_ORDER: GGMLFileQuantizationType[] = [
 	GGMLFileQuantizationType.F32,
 	GGMLFileQuantizationType.BF16,
 	GGMLFileQuantizationType.F16,
+	GGMLFileQuantizationType.Q8_K_XL,
 	GGMLFileQuantizationType.Q8_0,
 
 	// 6-bit quantizations
+	GGMLFileQuantizationType.Q6_K_XL,
 	GGMLFileQuantizationType.Q6_K,
 
 	// 5-bit quantizations
-	GGMLFileQuantizationType.Q5_0,
-	GGMLFileQuantizationType.Q5_1,
+	GGMLFileQuantizationType.Q5_K_XL,
 	GGMLFileQuantizationType.Q5_K_M,
 	GGMLFileQuantizationType.Q5_K_S,
+	GGMLFileQuantizationType.Q5_0,
+	GGMLFileQuantizationType.Q5_1,
 
 	// 4-bit quantizations
+	GGMLFileQuantizationType.Q4_K_XL,
 	GGMLFileQuantizationType.Q4_K_M,
 	GGMLFileQuantizationType.Q4_K_S,
 	GGMLFileQuantizationType.IQ4_NL,
 	GGMLFileQuantizationType.IQ4_XS,
 	GGMLFileQuantizationType.Q4_0_4_4,
 	GGMLFileQuantizationType.Q4_0_4_8,
 	GGMLFileQuantizationType.Q4_0_8_8,
-	GGMLFileQuantizationType.Q4_0,
 	GGMLFileQuantizationType.Q4_1_SOME_F16,
+	GGMLFileQuantizationType.Q4_0,
 	GGMLFileQuantizationType.Q4_1,
 	GGMLFileQuantizationType.Q4_2,
 	GGMLFileQuantizationType.Q4_3,
 
 	// 3-bit quantizations
+	GGMLFileQuantizationType.Q3_K_XL,
 	GGMLFileQuantizationType.Q3_K_L,
 	GGMLFileQuantizationType.Q3_K_M,
 	GGMLFileQuantizationType.Q3_K_S,
@@ -93,6 +107,7 @@ export const GGUF_QUANT_ORDER: GGMLFileQuantizationType[] = [
 	GGMLFileQuantizationType.IQ3_XXS,
 
 	// 2-bit quantizations
+	GGMLFileQuantizationType.Q2_K_XL,
 	GGMLFileQuantizationType.Q2_K,
 	GGMLFileQuantizationType.Q2_K_S,
 	GGMLFileQuantizationType.IQ2_M,