broaden shortestcovint to fit collection

[palday]

I broadened the type restriction so that some of the stuff I'm working on in MixedModelsPermutations can use shortestcovint without adding needing a new method definition for MixedModelPermutation.

Thanks for contributing!

Did behavior change? Did you add need features? If so, please update NEWS.md

• add entry in NEWS.md
• after opening this PR, add a reference and run docs/NEWS-update.jl to update the cross-references.

Should we release your changes right away? If so, bump the version:

• I've bumped the version appropriately

[palday]

If it weren't for the checklist, I would have forgotten the NEWS entry this time.

[codecov]

Codecov Report

Merging #598 (4ced8f0) into main (12a60ba) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #598   +/-   ##
=======================================
  Coverage   96.36%   96.36%           
=======================================
  Files          28       28           
  Lines        2695     2695           
=======================================
  Hits         2597     2597           
  Misses         98       98           

Impacted Files	Coverage Δ
src/bootstrap.jl	99.37% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 12a60ba...4ced8f0. Read the comment docs.

[dmbates]

Good to see you have updated NEWS.md. We must maintain standards 😁