nnet::multinom with wide format data

[strengejacke]

Fixes #905

[codecov]

Codecov Report

Merging #906 (0b19063) into main (4cd79a7) will increase coverage by 0.10%.
The diff coverage is 100.00%.

❗ Current head 0b19063 differs from pull request most recent head 3967bee. Consider uploading reports for the commit 3967bee to get more accurate results

@@            Coverage Diff             @@
##             main     #906      +/-   ##
==========================================
+ Coverage   57.32%   57.43%   +0.10%     
==========================================
  Files         186      186              
  Lines       13889    13906      +17     
==========================================
+ Hits         7962     7987      +25     
+ Misses       5927     5919       -8     

Files	Coverage Δ
R/methods_brglm2.R	83.45% <100.00%> (+9.32%)	⬆️