pseudo-normal-zz after scroll
Handle v:searchforward to handle `n` and `N`
Fix to use search flag for searchpos()
Fix to limit the `topline` value
Fix window scroll feature using appropriate sort()
Tiny code change and add TODO
spec: incremental scroll feature spec
spec: Add note for skipped test of o_v, o_V, and o_Ctrl-v
Add comment and remove some TODO
Merge branch 'improve-scroll-window' into dev

- including some other fix and specs