update readme.md

readme.md

@@ -103,7 +103,7 @@ You can store named colors in the `:root` selector at the top of the `<style>` t
 ## data persistence
 your task tree is automatically saved to your browser's local storage after each edit. this ensures your tasks will persist even if you close the browser or refresh the page.
 
-**⚠️ warning:** clearing your browsing data may erase your saved tasks. use the [export feature](#importingexporting) to create a backup before clearing your browsing data.
+**⚠️ warning:** clearing your browsing data may erase your saved tasks. use the [export feature](#importingexporting) to create a manual backup before clearing your browsing data.
 
 ## browser compatibility
 this application is designed to run on modern web browsers with javascript enabled. mobile browsers are supported, but a physical keyboard is required (for now).