readline: update to 8.2.

New Features in Readline

a. There is now an HS_HISTORY_VERSION containing the version number of the
  history library for applications to use.

b. History expansion better understands multiple history expansions that may
  contain strings that would ordinarily inhibit history expansion (e.g.,
  `abc!$!$').

c. There is a new framework for readline timeouts, including new public
  functions to set timeouts and query how much time is remaining before a
  timeout hits, and a hook function that can trigger when readline times
  out. There is a new state value to indicate a timeout.

d. Automatically bind termcap key sequences for page-up and page-down to
  history-search-backward and history-search-forward, respectively.

e. There is a new `fetch-history' bindable command that retrieves the history
  entry corresponding to its numeric argument. Negative arguments count back
  from the end of the history.

f. `vi-undo' is now a bindable command.

g. There is a new option: `enable-active-region'. This separates control of
  the active region and bracketed-paste. It has the same default value as
  bracketed-paste, and enabling bracketed paste enables the active region.
  Users can now turn off the active region while leaving bracketed paste
  enabled.

h. rl_completer_word_break_characters is now `const char *' like
  rl_basic_word_break_characters.

i. Readline looks in $LS_COLORS for a custom filename extension
  (*.readline-colored-completion-prefix) and uses that as the default color
  for the common prefix displayed when `colored-completion-prefix' is set.

j. Two new bindable string variables: active-region-start-color and
  active-region-end-color. The first sets the color used to display the
  active region; the second turns it off. If set, these are used in place
  of terminal standout mode.

k. New readline state (RL_STATE_EOF) and application-visible variable
  (rl_eof_found) to allow applications to detect when readline reads EOF
  before calling the deprep-terminal hook.

l. There is a new configuration option: --with-shared-termcap-library, which
  forces linking the shared readline library with the shared termcap (or
  curses/ncurses/termlib) library so applications don't have to do it.

m. Readline now checks for changes to locale settings (LC_ALL/LC_CTYPE/LANG)
  each time it is called, and modifies the appropriate locale-specific display
  and key binding variables when the locale changes.

(wiz)