docs(cli): add hint in convert subcommand

crates/cli/src/args/convert.rs

@@ -25,7 +25,7 @@ pub(crate) struct Args {
  /// Path containing the hkx/xml file/directory
  #[clap(short, long)]
  pub input: PathBuf,
- /// Output path
+ /// Output path (If not specified, it is automatically created in the same location as the input path.)
  #[clap(short, long)]
  pub output: Option<PathBuf>,