- Do not turn "other accounts" into a comma-delimited string when the
report is constructed, but pass `AccountName`s up the chain. This
requires modifying the `AccountTransactionsReportItem` type to contain
`[AccountName]` rather than `Text`.
- Perform the account name summarization
(`Hledger.Data.AccountName.accountSummarizedName`) closer to the
actual rendering of the report, so that different report formats can
choose summarization strategy.
- Continue to summarize as before for terminal/text output (ie.
human-readable). Do not summarize any more for machine-readable output
(csv/html/fods).
Follow-on from the brick 1.0 migration work (#1889, #1919).
These new types aim to be more restrictive, allowing fewer invalid
states, and easier to inspect and debug. The screen types store only
state, not behaviour (functions), and there is no longer a circular
dependency between UIState and Screen.
