gather - show all failed edges in error message

[atravitz]

Closes #1101

Checklist

• Added a news entry

Developers certificate of origin

• I certify that this contribution is covered by the MIT License here and the Developer Certificate of Origin at https://developercertificate.org/.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.82%. Comparing base (870463b) to head (78ba28e).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1095      +/-   ##
==========================================
- Coverage   93.56%   91.82%   -1.74%     
==========================================
  Files         137      137              
  Lines       10105    10096       -9     
==========================================
- Hits         9455     9271     -184     
- Misses        650      825     +175     

Flag	Coverage Δ
fast-tests	91.82% <100.00%> (?)
slow-tests	?

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[IAlibay]

This looks fine to me, but the error message seems like it might be a bit too unweildy.

Ideally we want something that's easy to parse for edges rather than a lot of text around each printed line.

[jthorton]

One not blocking suggestion for info on restarting, otherwise this is great!

[github-actions]

No API break detected ✅