This is the command invoked repeatedly to make the changes:
:%s/^\(.*\)|\%(\*\(\d\+\)\)\?$\n\1|\%(\*\(\d\+\)\)\?$/\=submatch(1)..'|*'..(max([str2nr(submatch(2)),1])+max([str2nr(submatch(3)),1]))/g
msg_puts_display was more complex than necessary in nvim, as in
nvim, it no longer talks directly with a terminal.
In particular we don't need to scroll the grid before emiting the last
char. The TUI already takes care of things like that, for terminals
where it matters.
Problem: Various parts of code not covered by tests.
Solution: Add more tests. (Yegappan Lakshmanan, closesvim/vim#6300)
845e0ee594
Omit test_iminsert.vim: the commit that created this file was N/A.
Omit test_viminfo.vim: the added tests are N/A.