vim-patch:9.1.{0211,0215}

[luukvbaal]

vim-patch:9.1.0211: page-wise scrolling does not support smooth-scrolling

Problem: Page-wise scrolling with Ctrl-F/Ctrl-B implements
it's own logic to change the topline and cursor.
In doing so, skipcol is not handled properly for
'smoothscroll', and virtual lines.
Solution: Re-use the logic from Ctrl-E/Ctrl-Y while staying
backward compatible as much as possible.

vim/vim@b9f5b95

vim-patch:9.1.0215: Half-page scrolling does not support smooth-scrolling

Problem: Page-wise scrolling with Ctrl-D/Ctrl-U implements
it's own logic to change the topline and cursor.
More logic than necessary for scrolling with Ctrl-F/Ctrl-B
was removed in patch 9.1.0211.
Solution: Re-use the logic from Ctrl-E/Ctrl-Y/Ctrl-F/Ctrl-B while
staying backward compatible as much as possible.
Restore some of the logic that determined how many lines will
be scrolled (Luuk van Baal)

vim/vim@5a2e3ec

[zeertzjq]

Please use w_height_inner instead of w_height.