Update user guide wrt force_new

[forman]

Updated user guide wrt force_new. Completes #73.

Checklist (strike out non-applicable):

• Changes documented in CHANGES.md
• Related issue exists and is referred to in the PR description and CHANGES.md
• Added docstrings and API docs for any new/modified user-facing classes and functions
• Changes/features documented in docs/*
• Unit-tests adapted/added for changes/features
• Test coverage remains or increases (target 100%)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.92%. Comparing base (249b7e8) to head (882f70a).

❗ Current head 882f70a differs from pull request most recent head b00ae1c. Consider uploading reports for the commit b00ae1c to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #76   +/-   ##
=======================================
  Coverage   99.92%   99.92%           
=======================================
  Files          26       26           
  Lines        1396     1396           
=======================================
  Hits         1395     1395           
  Misses          1        1           

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[forman]

@thomasstorm merci!