fix(app): fix lint issue with string cloning

Signed-off-by: Deep Panchal <deep302001@gmail.com>

src/app.rs

@@ -153,7 +153,7 @@ impl App {
  });
  })?;
  }
- Action::StatusLine(ref s) => self.state.status_line = s.clone(),
+ Action::StatusLine(ref s) => self.state.status_line.clone_from(s),
  Action::FocusNext => match self.state.mode {
  Mode::Book => {
  self.state.mode = Mode::Page;