chore(lean.bib): restore comment explaining how to run bibtool · leanprover-community/leanprover-community.github.io@d9b7088

lean.bib is not normalized.

run 'bibtool --preserve.key.case=on --preserve.keys=on --pass.comments=on --print.use.tab=off -s -i lean.bib -o lean.bib' to fix the issue.

Process completed with exit code 1.