Write better PR title, PR comments, checklist, communication

[bobleesj]

Leaving an issue here based on this PR electronmicroscopy/quantem#179

Documentation further refines on

1. How to use checklists
2. How to write an effective PR title
3. How to communicate between Author and Reviewer
4. How to resolve conflict
5. How to display code's results

[bobleesj]

electronmicroscopy/quantem#180

Another example reference to improve to doc.

[bobleesj]

Guide contributors to focus on identifying the correct "problems" for end-users, not the code.

Ex) People buy screw drivers to hang sth on the wall, not because they want to fix the wall.