message: Update history help.
diff: @@ -15,7 +15,7 @@ use ion_shell::{
  use ion_sys::SIGHUP;
  use itertools::Itertools;
  use liner::{Buffer, Context, KeyBindings};
  -use std::{cell::RefCell, fs::OpenOptions, io, path::Path, rc::Rc};
  +use std::{cell::RefCell, fs::OpenOptions, io, io::Write, path::Path, rc::Rc};
  use xdg::BaseDirectories;
  pub const MAN_ION: &str = "NAME
  @@ -45,10 +45,19 @@ pub(crate) const MAN_HISTORY: &str = r#"NAME
  history - print command history
  SYNOPSIS
  - history
  + history [option]
  DESCRIPTION
  - Prints the command history."#;
  + Prints or manupulate the command history.
  +
  +OPTIONS:
  + +inc_append: Append each command to history as entered.
  + -inc_append: Default, do not append each command to history as entered.
  + +shared: Share history between shells using the same history file, implies inc_append.
  + -shared: Default, do not share shell history.
  + +duplicates: Default, allow duplicates in history.
  + -duplicates: Do not allow duplicates in history.
  +"#;
  pub struct InteractiveBinary<'a> {
  context: Rc<RefCell<Context>>,
  