Use sys.exit to quit via system tray. Fix pip install cmd in Readme

Readme.md

@@ -136,7 +136,7 @@ pip install --upgrade khoj-assistant
    ``` shell
    git clone https://github.com/debanjum/khoj && cd khoj
    python -m venv .venv && source .venv/bin/activate
-   pip install
+   pip install .
    ```
 ##### 2. Configure
    - Set `input-files` or `input-filter` in each relevant `content-type` section of `khoj_sample.yml`

src/main.py

@@ -121,7 +121,7 @@ def create_system_tray():
     menu_actions = [
         ('Search', lambda: webbrowser.open('http://localhost:8000/')),
         ('Configure', lambda: webbrowser.open('http://localhost:8000/config')),
-        ('Quit', quit),
+        ('Quit', sys.exit),
     ]
 
     # Add the menu actions to the menu