Improve wording and "fix example" (remove 3.13) on testing against pre-release

[yarikoptic]

Description:

3.13 was added in a mass tune up in 0b93645 , without adjusting the wording. With 3.13 listed there too, example does not really make much sense. So I decided to make it explicit in wording and remove 3.13, so whenever next refactoring to add 3.14 to be added to every line where 3.13 is -- this would not even come to attention

Check list:

• Mark if documentation changes are required.
• Mark if tests were added or updated to cover the changes.

[GIgako19929]

This pull request includes updates to the documentation to clarify the behavior of the allow-prereleases flag and to correct an example workflow.

Documentation improvements:

• docs/advanced-usage.md: Updated the description to clarify that the allow-prereleases flag defaults to false and provided a more accurate historical reference for when Python 3.12 was not generally available.
• docs/advanced-usage.md: Corrected the example workflow by removing the unsupported Python 3.13 version from the matrix configuration.