Bug was introduced in commit 2a99b3d456
in an effort to get rid of partial List.tail,
because GHC-9.8 started to warn about it.
Problem is that the rewritten code with tailDef always removes the last account,
whereas the original intention was to replace all accounts by a comma except the last one.
addCommas should prepare a comma separated list like List.intercalate.
A simple web-based user interface for the hledger accounting system,
providing a more modern UI than the command-line or terminal interfaces.
It can be used as a local single-user UI, or as a multi-user UI for
viewing/adding/editing on the web.
b74815287d