fix session not being closed

hn.py

@@ -95,7 +95,7 @@ class Client:
         c = self.screen.getch()
         story = self.loadedstories[self.topstories[self.story_pos + self.cursor_pos]]
         if c == ord('q'):  # Quit
-            self.exit()
+            await self.exit()
         elif c == curses.KEY_UP:
             self.cursor_pos -= 1
             if self.cursor_pos < 0:
@@ -168,8 +168,8 @@ class Client:
             self.draw()
             await self.handle_input()
 
-    def exit(self):
-        self.session.close()
+    async def exit(self):
+        await self.session.close()
         curses.endwin()
         import sys
         sys.exit(0)