Fix escape not exiting insert mode (#712)

Regression due to #635 where escape key in insert mode
would not exit normal mode. This happened due to hard
coding the escape key to cancel a sticky keymap node.

helix-term/src/keymap.rs

@@ -287,14 +287,15 @@ impl Keymap {
     /// sticky node is in use, it will be cleared.
     pub fn get(&mut self, key: KeyEvent) -> KeymapResult {
         if let key!(Esc) = key {
-            if self.state.is_empty() {
-                self.sticky = None;
-            }
+            if !self.state.is_empty() {
                 return KeymapResult::new(
+                    // Note that Esc is not included here
                     KeymapResultKind::Cancelled(self.state.drain(..).collect()),
                     self.sticky(),
                 );
             }
+            self.sticky = None;
+        }
 
         let first = self.state.get(0).unwrap_or(&key);
         let trie_node = match self.sticky {