Update CHANGELOG and man pages

CHANGELOG.md

@@ -1,6 +1,50 @@
 CHANGELOG
 =========
 
+0.19.0
+------
+
+- Added "reload" action for dynamically updating the input list without
+  restarting fzf. See https://github.com/junegunn/fzf/issues/1750 to learn
+  more about it.
+  ```sh
+  # Using fzf as the selector interface for ripgrep
+  RG_PREFIX="rg --column --line-number --no-heading --color=always --smart-case "
+  INITIAL_QUERY="foo"
+  FZF_DEFAULT_COMMAND="$RG_PREFIX '$INITIAL_QUERY'" \
+    fzf --bind "change:reload:$RG_PREFIX {q} || true" \
+        --ansi --phony --query "$INITIAL_QUERY"
+  ```
+- `--multi` now takes an optional integer argument which indicates the maximum
+  number of items that can be selected
+  ```sh
+  seq 100 | fzf --multi 3 --reverse --height 50%
+  ```
+- If a placeholder expression for `--preview` and `execute` action (and the
+  new `reload` action) contains `f` flag, it is replaced to the
+  path of a temporary file that holds the evaluated list. This is useful
+  when you multi-select a large number of items and the length of the
+  evaluated string may exceed [`ARG_MAX`][argmax].
+  ```sh
+  # Press CTRL-A to select 100K items and see the sum of all the numbers
+  seq 100000 | fzf --multi --bind ctrl-a:select-all \
+                   --preview "awk '{sum+=\$1} END {print sum}' {+f}"
+  ```
+- `deselect-all` no longer deselects unmatched items. It is now consistent
+  with `select-all` and `toggle-all` in that it only affects matched items.
+- Due to the limitation of bash, fuzzy completion is enabled by default for
+  a fixed set of commands. A helper function for easily setting up fuzzy
+  completion for any command is now provided.
+  ```sh
+  # usage: _fzf_setup_completion path|dir COMMANDS...
+  _fzf_setup_completion path git kubectl
+  ```
+- When you transform the input with `--with-nth`, the trailing white spaces
+  are removed.
+- See https://github.com/junegunn/fzf/milestone/15?closed=1 for more details
+
+[argmax]: https://unix.stackexchange.com/questions/120642/what-defines-the-maximum-size-for-a-command-single-argument
+
 0.18.0
 ------