Problem:  Although patch 9.1.0990 fixed a real problem/inconsistency,
          it also introduced new behavior that may break BWC and/or be
          unexpected. Before 9.1.0990, window commands could make the
          topframe smaller (without changing 'cmdheight'; quirk that is
          now fixed), but did not allow extending the topframe beyond
          the 'cmdheight' set by the user. After 9.1.0990, the user can
          reduce the 'cmdheight' below the value they set explicitly,
          through window commands, which may lead to confusion.
          (aftere v9.1.0990)
Solution: Store the value explicitly set by the user and clamp the
          'cmdheight' when resizing the topframe. This also applies to
          dragging laststatus, which in contrast to window commands
          _did_ allow reducing the 'cmdheight' to values below the one
          set by the user. So with this patch there is still new
          behavior, but I think in a way that is less surprising.
          While at it, also fix a Coverity warning, introduced in
          v9.1.0990 (Luuk van Baal)

https://github.com/vim/vim/commit/c97e8695353565d6b20adffa48aad47f6e09967f

Problem:  Inconsistent behavior when changing cmdheight by resizing the
          topframe through wincmds and dragging laststatus. Changing
          cmdheight by resizing the topframe does not trigger OptionSet.
Solution: Consolidate logic for changing the cmdheight, set the option
          value to handle side-effects (Luuk van Baal)

https://github.com/vim/vim/commit/e15cbc1af47e9dea90448c714eb4908e5d4302fc

vim-patch:9.0.0187: command line height changes when maximizing window height

Problem:  Command line height changes when maximizing window height.
Solution: Do not change the command line height. (closes vim/vim#10885)

https://github.com/vim/vim/commit/96bde99bf890acd9952863a02c1d15edca2000e1

Problem:  Unknown key mappings listed in substitute confirm message.
Solution: Include hints as to what the key mappings do.

Problem:
`termopen` has long been a superficial wrapper around `jobstart`, and
has no real purpose. Also, `vim.system` and `nvim_open_term` presumably
will replace all features of `jobstart` and `termopen`, so centralizing
the logic will help with that.

Solution:
- Introduce `eval/deprecated.c`, where all deprecated eval funcs will live.
- Introduce "term" flag of `jobstart`.
- Deprecate `termopen`.

When a terminal application running inside the terminal emulator sets
the cursor shape or blink status of the cursor, update the cursor in the
parent terminal to match.

This removes the "virtual cursor" that has been in use by the terminal
emulator since the beginning. The original rationale for using the
virtual cursor was to avoid having to support additional UI methods to
change the cursor color for other (non-TUI) UIs, instead relying on the
TermCursor and TermCursorNC highlight groups.

The TermCursor highlight group is now used in the default 'guicursor'
value, which has a new entry for Terminal mode. However, the
TermCursorNC highlight group is no longer supported: since terminal
windows now use the real cursor, when the window is not focused there is
no cursor displayed in the window at all, so there is nothing to
highlight. Users can still use the StatusLineTermNC highlight group to
differentiate non-focused terminal windows.

BREAKING CHANGE: The TermCursorNC highlight group is no longer supported.

Problem:
Since e049c6e4c08a, most statusline-like UI elements can combine
highlight attrs, except for sign/statuscolumn.

Solution:
Implement for sign/statuscolumn.

Problem:  not possible to configure :messages
Solution: add the 'messagesopt' option (Shougo Matsushita)

closes: vim/vim#16068

https://github.com/vim/vim/commit/51d4d84d6a7159c6ce9e04b36f8edc105ca3794b

Co-authored-by: Shougo Matsushita <Shougo.Matsu@gmail.com>
Co-authored-by: h_east <h.east.727@gmail.com>

Problem:  %! item not allowed for 'rulerformat'
          (yatinlala)
Solution: also allow to use %! for rulerformat option
          (Yegappan Lakshmanan)

fixes: vim/vim#16091
closes: vim/vim#16118

https://github.com/vim/vim/commit/ac023e8baae65584537aa3c11494dad6f71770af

Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>

Problem:  curswant not set on gm in folded line
          (citizenmatt)
Solution: in a folded line, call update_curswant_force()

fixes: vim/vim#11596
closes: vim/vim#11994
closes: vim/vim#15398

https://github.com/vim/vim/commit/9848face747ba91282d34a96dcb966bcb410bf2b

Co-authored-by: Christian Brabandt <cb@256bit.org>