Bugfix: CategoryRelations, missing XCAT error message

[Magnus167]

Closes issue #909

[codecov]

Codecov Report

Merging #964 (53a113f) into develop (d217396) will decrease coverage by 0.04%.
Report is 1 commits behind head on develop.
The diff coverage is 52.63%.

❗ Current head 53a113f differs from pull request most recent head 8941742. Consider uploading reports for the commit 8941742 to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #964      +/-   ##
===========================================
- Coverage    63.80%   63.76%   -0.04%     
===========================================
  Files           40       40              
  Lines         4636     4648      +12     
===========================================
+ Hits          2958     2964       +6     
- Misses        1678     1684       +6     

Files Changed	Coverage Δ
macrosynergy/panel/category_relations.py	36.75% <52.63%> (+0.54%)	⬆️