fix: missing automatic man page generation for subcommands

The main man page would point to man pages for subcommands, which
weren't created automatically by the man page xtask.

xtask/src/main.rs

@@ -61,7 +61,7 @@ automation.",
                     .long("output")
                     .value_name("PATH")
                     .default_value("misc")
-                    .help("Output directory for the generated man page.")
+                    .help("Output directory for the generated man pages.")
                     .value_parser(PathBufValueParser::new())])
                 .about("Automatic man page generation."),
             clap::Command::new("generate-shell-completion")
@@ -110,15 +110,12 @@ fn generate_manpage(subcommand_arguments: &ArgMatches) -> Result<(), DynError> {
         .get_one::<PathBuf>("output")
         .unwrap_or(&default_output_directory);
     let cmd = ncspot::program_arguments();
-    let man = clap_mangen::Man::new(cmd);
-    let mut buffer: Vec<u8> = Default::default();
 
     if *output_directory == default_output_directory {
         fs::create_dir_all(DEFAULT_OUTPUT_DIRECTORY)?;
     }
 
-    man.render(&mut buffer)?;
-    std::fs::write(output_directory.join("ncspot.1"), buffer)?;
+    clap_mangen::generate_to(cmd, output_directory)?;
 
     Ok(())
 }