made listfields option naming consistent

Author: datsom1

db_diff/cli.py

@@ -126,15 +126,15 @@ def load(filename, key, input_format, encoding="utf-8"):
     help="Use streaming mode for very large CSV/TSV files (requires files to be sorted by key).",
 )
 @click.option(
-    "--list-fields",
+    "--listfields",
     is_flag=True,
     help="List available fields/columns in the input files and exit.",
 )
 @click.version_option()
 def cli(
     previous, current, key, input_format,
     show_unchanged, encoding, show_time, output, output_file, output_path,
-    fields, ignorefields, streaming, list_fields
+    fields, ignorefields, streaming, listfields
 ):
     """
     Compare the differences between two CSV or JSON files.
@@ -147,7 +147,7 @@ def cli(
         raise click.ClickException(f"Unsupported file format: {detected_format}")
 
     # List fields and exit
-    if list_fields:
+    if listfields:
         try:
             if detected_format == "json":
                 with open(previous, encoding=encoding) as f: