Use NO_COLOR env variable check also for help screen

src/app.rs

@@ -1,10 +1,17 @@
 use clap::{crate_version, App, AppSettings, Arg};
 
 pub fn build_app() -> App<'static, 'static> {
+    let clap_color_setting =
+        if std::env::var_os("NO_COLOR").is_none() {
+            AppSettings::ColoredHelp
+        } else {
+            AppSettings::ColorNever
+        };
+
     let mut app = App::new("fd")
         .version(crate_version!())
         .usage("fd [FLAGS/OPTIONS] [<pattern>] [<path>...]")
-        .setting(AppSettings::ColoredHelp)
+        .setting(clap_color_setting)
         .setting(AppSettings::DeriveDisplayOrder)
         .after_help(
             "Note: `fd -h` prints a short and concise overview while `fd --help` gives all \