implemented Ctrl+R command history searching and command history expansion with '\!'

src/builtin/keymap.rs

@@ -111,11 +111,6 @@ impl KeyMap {
     expand_keymap(&self.action)
   }
   pub fn compare(&self, other: &[KeyEvent]) -> KeyMapMatch {
-    log::debug!(
-      "Comparing keymap keys {:?} with input {:?}",
-      self.keys_expanded(),
-      other
-    );
     let ours = self.keys_expanded();
     if other == ours {
       KeyMapMatch::IsExact