Merge pull request #51 from maphew/patch-2

use noteId of `root` to export all notes in the db

Author: Nriver

README.md

@@ -259,7 +259,7 @@ ea.set_day_note(date, new_content)
 
 ### 📤 Export note
 
-Export note comes in two formats `html` or `markdown`/`md`.
+Export note comes in two formats `html` or `markdown`/`md`. Setting `noteId` to `root` will export all notes.
 
 ```python
 res = ea.export_note(