Add use case examples to make the documentation more friendly

[orhun]

Is your feature request related to a problem? Please describe.

A comment from Discord:

I found the doc examples lacking in terms of what options should be used for different workflows. Different users would want to generate changelogs at different points:

• a new unreleased changelog update on each push to a development branch, and then a "release" when development is merged into main
• a new unreleased update on each push to a main branch, and then a "release" when a tag is pushed

I found the docs confusing because I didn't know what combination of CLI options I should be using for my workflow.

Describe the solution you'd like

The examples are mostly just "use this flag to do this". Updates on this would help a lot for newbs to this like me

Describe alternatives you've considered

None.

Additional context

https://discord.com/channels/1093977388892819553/1094287935580418069/1202509640584265728