|inputdialog()| support custom highlighting.
  |input()-highlight|
- (Experimental) *g:Nvim_color_cmdline* Command-line (|:|) is colored by
  callback defined in `g:Nvim_color_cmdline` (this callback is for testing
  only, and will be removed in the future).

Commands:
- |:checkhealth|
- |:drop| is always available
- |:Man| is available by default, with many improvements such as completion
- |:match| can be invoked before highlight group is defined
- |:source| works with Lua
  User commands can support |:command-preview| to show results as you type
- |:write| with "++p" flag creates parent directories.

Events (autocommands):
- Fixed inconsistent behavior in execution of nested autocommands #23368
- |RecordingEnter|
- |RecordingLeave|
- |SearchWrapped|
- |Signal|
- |TabNewEntered|
- |TermClose|
- |TermOpen|
- |TermResponse| is fired for any OSC sequence received from the terminal,
  instead of the Primary Device Attributes response. |v:termresponse|
- |UIEnter|
- |UILeave|

Functions:
- |dictwatcheradd()| notifies a callback whenever a |Dict| is modified
- |dictwatcherdel()|
- |menu_get()|
- |msgpackdump()|, |msgpackparse()| provide msgpack de/serialization
- |stdpath()|
- |system()|, |systemlist()| can run {cmd} directly (without 'shell')
- |matchadd()| can be called before highlight group is defined
- |tempname()| tries to recover if the Nvim |tempdir| disappears.
- |writefile()| with "p" flag creates parent directories.
- |searchcount()|'s maximal value is raised from 99 to 999.

Highlight groups:
- |highlight-blend| controls blend level for a highlight group
- |expr-highlight| highlight groups (prefixed with "Nvim")
- |hl-NormalFloat| highlights floating window
- |hl-FloatBorder| highlights border of a floating window
- |hl-FloatTitle| highlights title of a floating window
- |hl-FloatFooter| highlights footer of a floating window
- |hl-NormalNC| highlights non-current windows
- |hl-MsgArea| highlights messages/cmdline area
- |hl-MsgSeparator| highlights separator for scrolled messages
- |hl-Substitute|
- |hl-TermCursor|
- |hl-WinSeparator| highlights window separators
- |hl-Whitespace| highlights 'listchars' whitespace
- |hl-WinBar| highlights 'winbar'
- |hl-WinBarNC| highlights non-current window 'winbar'

Input/Mappings:
- ALT (|META|) chords always work (even in the |TUI|). Map |<M-| with any key:
  <M-1>, <M-BS>, <M-Del>, <M-Ins>, <M-/>, <M-\>, <M-Space>, <M-Enter>, etc.
  - Case-sensitive: <M-a> and <M-A> are two different keycodes.
- ALT may behave like <Esc> if not mapped. |i_ALT| |v_ALT| |c_ALT|

Normal commands:
- |gO| shows a filetype-defined "outline" of the current buffer.
- |Q| replays the last recorded macro instead of switching to Ex mode (|gQ|).

Options:

- `:set {option}<` removes local value for all |global-local| options.
- `:setlocal {option}<` copies global value to local value for all options.
- 'ambiwidth'   cannot be set to empty.
- 'autoread'    works in the terminal (if it supports "focus" events)
- 'background'  cannot be set to empty.
- 'cpoptions'   flags: |cpo-_|
- 'eadirection' cannot be set to empty.
- 'exrc'        searches for ".nvim.lua", ".nvimrc", or ".exrc" files. The
                user is prompted whether to trust the file.
- 'fileformat'  cannot be set to empty.
- 'fillchars'   flags: "msgsep", "horiz", "horizup", "horizdown",
                "vertleft", "vertright", "verthoriz"
- 'foldcolumn'  supports up to 9 dynamic/fixed columns
- 'guicursor'   works in the terminal (TUI)
- 'inccommand'  shows interactive results for |:substitute|-like commands
                and |:command-preview| commands
- 'jumpoptions'
    - "view" tries to restore |mark-view| when moving through the jumplist.
    - "clean" removes unloaded buffers from the jumplist.
- the |jumplist|, |changelist|, |alternate-file| or using |mark-motions|.
- 'laststatus'  global statusline support
- 'mousemodel'  cannot be set to empty.
- 'mousescroll' amount to scroll by when scrolling with a mouse
- 'pumblend'    pseudo-transparent