Fix #2692

So you can "rotate" through the different options with a single binding.

  fzf --preview 'cat {}' \
      --bind 'ctrl-/:change-preview-window(70%|down,40%,border-horizontal|hidden|)'

Close #2376

The new actions are named with 'change-' prefix to differentiate from
the pre-existing, one-off 'preview(...)' action.

Fix #2360
Fix #2505
Fix #2666

Related #2435
Related #2376
  - Can set up multiple bindings with different change-preview-window actions
  - Not possible to "rotate" through the options with a single binding
  - Enlarge or shrink not possible

Close #2422

Fix #2611

Close #2516

Fix #2508

Close #2502

Fix #2486

Close #2408

Close #2431

Fix #2373

  # Display top 3 lines as the fixed header
  fzf --preview 'bat --style=header,grid --color=always {}' --preview-window '~3'

Close #2358

Close #2331

- `--phony` renamed to `--disabled` for consistency
    - `--no-phony` is now `--enabled`
- Added `enable-search`, `disable-search`, and `toggle-search` actions
  for `--bind`
- Added `--color` options: `query` and `disabled`

Close #2303

"alt-" with any case-sensitive character is allowed

This is the opposite of "first" (previously known as "top").

Close #2270

Close #2241

Fix #2239

Instead of drawing the window border in Vim using an extra window,
extend the --border option so that we do can it natively.

Close #2223
Fix #2184

New color name: input

Close #1663

  fzf --preview 'for i in $(seq 100000); do
    (( i % 200 == 0 )) && printf "\033[2J"
    echo "$i"
    sleep 0.01
  done'

Fix #2212

    # Will start rendering after 200ms, update every 100ms
    fzf --preview 'for i in $(seq 100); do echo $i; sleep 0.01; done'

    # Should print "Loading .." message after 500ms
    fzf --preview 'sleep 1; for i in $(seq 100); do echo $i; sleep 0.01; done'

    # The first line should appear after 200ms
    fzf --preview 'date; sleep 2; date'

    # Should not render before enough lines for the scroll offset are ready
    rg --line-number --no-heading --color=always ^ |
      fzf --delimiter : --ansi --preview-window '+{2}-/2' \
          --preview 'sleep 1; bat --style=numbers --color=always --pager=never --highlight-line={2} {1}'