Issue 23: Switch sampling order to truncate and then censor

[seabbs]

Description

This PR closes #23 and as the title switches the order of the sampling process which I think better reflects our assumption about the process (that observation is conditional on the continuous event and not the lower bound of the observation window.

This could be the wrong assumption or in a more complex setting it could be that observation is based on the end of the secondary event window.

I think if we merge this we may want a issue to track this in case we need to provide options (that I think will confuse the majority of users).

Checklist

• My PR is based on a package issue and I have explicitly linked it.
• I have included the target issue or issues in the PR title in the for Issue(s) issue-numbers: PR title
• I have read the contribution guidelines.
• I have tested my changes locally.
• I have added or updated unit tests where necessary.
• I have updated the documentation if required.
• My code follows the established coding standards.
• I have added a news item linked to this PR.
• I have reviewed CI checks for this PR and addressed them as far as I am able.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.43%. Comparing base (59a4182) to head (cd21550).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #26   +/-   ##
=======================================
  Coverage   99.43%   99.43%           
=======================================
  Files           6        6           
  Lines         178      178           
=======================================
  Hits          177      177           
  Misses          1        1           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[seabbs]

LGTM (self-review)