`sankey.py` doesn't fully work with the latest hledger anymore.

[basvandijk]

I think https://github.com/simonmichael/hledger/commit/3e2685fe95a8b0d4ee5f1614cd82de1dbac60c0b broke sankey.py because, before that commit, accounts in --tree mode were displayed with their full name which sankey.py expects but that commit displayed the accounts with just their displayName indented with 2 times the depth amount of non-breaking spaces.

I guess we could work around this in sankey.py by re-constructing the full account names by replacing the non-breaking spaces with the parent account.

[basvandijk]

CC @simonmichael , @thielema