Apply suggestions from code review

Author: ngxson

convert_hf_to_gguf.py

@@ -6630,7 +6630,7 @@ def parse_args() -> argparse.Namespace:
         help="path to write to; default: based on input. {ftype} will be replaced by the outtype.",
     )
     parser.add_argument(
-        "--outtype", type=str, choices=["f32", "f16", "bf16", "q4_0", "q8_0", "tq1_0", "tq2_0", "auto"], default="f16",
+        "--outtype", type=str, choices=["f32", "f16", "bf16", "q8_0", "tq1_0", "tq2_0", "auto"], default="f16",
         help="output format - use f32 for float32, f16 for float16, bf16 for bfloat16, q8_0 for Q8_0, tq1_0 or tq2_0 for ternary, and auto for the highest-fidelity 16-bit float type depending on the first loaded tensor type",
     )
     parser.add_argument(
@@ -6762,7 +6762,6 @@ def main() -> None:
         "f32": gguf.LlamaFileType.ALL_F32,
         "f16": gguf.LlamaFileType.MOSTLY_F16,
         "bf16": gguf.LlamaFileType.MOSTLY_BF16,
-        "q4_0": gguf.LlamaFileType.MOSTLY_Q4_0,
         "q8_0": gguf.LlamaFileType.MOSTLY_Q8_0,
         "tq1_0": gguf.LlamaFileType.MOSTLY_TQ1_0,
         "tq2_0": gguf.LlamaFileType.MOSTLY_TQ2_0,