(unexported module). These are used in both the man and ms
writers.
Moved groffEscape out of Text.Pandoc.Writers.Shared [cancels earlier
API change from adding it, which was after last release].
This fixes strong/code combination on man (should be `\f[CB]` not
`\f[BC]`), mentioned in #4973.
Updated tests.
Closes#4975.
* Markdown writer now includes a blank line at the end
of the row in a single-row multiline table, to prevent it from being
interpreted as a simple table. Closes#4578.
* Markdown reader does a better job computing the relative width of
the last column in a multiline table, so we can round-trip tables
without constantly shrinking the last column.
