Add Detailed Examples to the "Usage" Section of README.md

[AgumasD]

Summary of Changes

This PR improves the "Usage" section of the README.md by adding detailed examples for several commands. These examples aim to provide practical use cases to help users better understand and utilize todo.txt-cli.

Changes Made

1. Added an example for the list command with filters and logical operators.
2. Included a practical example for replace, showcasing how to update an existing task.
3. Detailed the move command with a clear explanation of SRC and DEST arguments and an example.
4. Added examples for prioritizing tasks using pri and appending text to tasks with append.

Why This Change is Needed

The previous documentation provided only minimal examples, making it harder for users to grasp the full functionality of the commands. By adding these detailed examples, we aim to improve the onboarding experience for new users and enhance the usability of the tool.

Fixes #445