Update flow_cap_min description

[brynpickering]

Fixes #653.

Summary of changes in this pull request

• Re-word description of flow_cap_min to match suggestion by @sstroemer

Reviewer checklist

• Test(s) added to cover contribution
• Documentation updated
• Changelog updated
• Coverage maintained or improved

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.98%. Comparing base (389e9f2) to head (2eba4eb).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #672   +/-   ##
=======================================
  Coverage   95.98%   95.98%           
=======================================
  Files          26       26           
  Lines        3981     3981           
  Branches      837      768   -69     
=======================================
  Hits         3821     3821           
  Misses         70       70           
  Partials       90       90           

[sjpfenninger]

Minor typo fixed.