You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: navigate.rs
    path of file: ./repos/delta/src/features
    
    the code of the file until where you have to start completion: use std::io::Write;
#[cfg(target_os = "windows")]
use std::io::{Error, ErrorKind};
use std::path::PathBuf;

use crate::config::Config;
use crate::features::OptionValueFunction;

pub fn make_feature() -> Vec<(String, OptionValueFunction)> {
    builtin_feature!([
        (
            "navigate",
            bool,
            None,
            _opt => true
        ),
        (
            "file-modified-label",
            String,
            None,
            _opt => "Δ"
        ),
        (
            "hunk-label",
            String,
            None,
            _opt => "•"
        )
    ])
}

// Construct the regexp used by less for paging, if --show-themes or --navigate is enabled.
pub fn make_navigate_regex(
    show_themes: bool,
    file_modified_label: &str,
  
    
fn get_less_hist_file() -> Option<PathBuf> {
    if let Some(home_dir) = dirs::home_dir() {
        match std::env::var("LESSHISTFILE").as_deref() {
            Ok("-") | Ok("/dev/null") => {
                // The user has explicitly disabled less history.
                None
            }
            Ok(path) => {
                // The user has specified a custom histfile
                Some(PathBuf::from(path))
            }
            Err(_) => {
                // The user is using the default less histfile location.
                let mut hist_file = home_dir;
                hist_file.push(if cfg!(windows) {
                    "_lesshst"
                } else {
                    ".lesshst"
                });
                Some(hist_file)
            }
        }
    } else {
        None
    }
}