Fix Field names containing '_items' crash field coverage

[VMRuiz]

Fixes #428

It only cover the case where the fields ends with "_items" but is prefixed with something else like "count_items".
Using only _items as field name is still not compatible with the coverage count. We may be able to make it work but it would require a significant rewrite of calculate_field_coverage

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.43%. Comparing base (6b3503b) to head (957104a).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #437   +/-   ##
=======================================
  Coverage   79.43%   79.43%           
=======================================
  Files          76       76           
  Lines        3229     3229           
  Branches      536      536           
=======================================
  Hits         2565     2565           
  Misses        593      593           
  Partials       71       71           

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