nano: Update to 5.6

nano: Update to 5.6

- Update nano from 5.5 to 5.6
- No update for rootfile
- Changelog
   Changes between v5.5 and v5.6:
    Benno Schulenberg (52):
      build: avoid a warning about duplicate symbol when building from tarball
      build: detect a build from git also when building out of tree
      build: include a workaround only for versions of ncurses that need it
      bump version numbers and add a news item for the 5.6 release
      color: do not look for another 'end' match after already finding one
      color: give highlighted text its own color, to not look like marked text
      color: recompile the file-probing regexes a little faster with REG_NOSUB
      color: use bright yellow to highlight a search match
      color: use inverse video for highlighting when there are no colors
      debug: add timing instruments to cache precalculation and screen refresh
      display: for a large paste or insertion, recalculate the multiline cache
      docs: correct the description of --quickblank for the changed base value
      docs: correct the formatting of a comment in the sample nanorc
      docs: correct the word order for Alt+D in the cheat sheet -- it changed
      docs: mention the new 'set highlightcolor' option
      docs: remove all mentions of --markmatch and 'set markmatch'
      docs: say that --minibar is modified by --constantshow and --stateflags
      feedback: make Full Justify show a message also when using --minibar
      gnulib: update to its current upstream state
      minibar: show a message a little longer when --quickblank isn't used
      minibar: show cursor position + character code only with --constantshow
      minibar: show the state flags only when --stateflags is used
      minibar: suppress the toggling feedback for M-C, but show it for M-Y/M-P
      options: remove --markmatch and 'set markmatch', as the behavior is gone
      painting: always do backtracking for the first row of the screen
      painting: trigger a refresh when a second start match appears on a line
      painting: trigger fewer unneeded full-screen refreshes
      painting: when finding an end match, set its multidata right away
      scrolling: keep centering after large paste, also when line numbers widen
      search: just highlight the found occurrence, instead of marking it
      search: make highlighting the standard, non-changeable behavior
      tweaks: avoid the vague possibility of advancing beyond end-of-line
      tweaks: be slightly more efficient in marking lines as WOULDBE
      tweaks: call wattron()/wattroff() only when actually painting something
      tweaks: correct a comment, improve another, and trim some verbosity
      tweaks: don't bother comparing virgin multidata with current situation
      tweaks: don't bother initializing freshly allocated multidata
      tweaks: don't bother wiping the multidata before recomputing it
      tweaks: elide a function that is now just one line
      tweaks: frob a condition, to be more concise, and reshuffle another
      tweaks: frob some comments, and adjust indentation after previous change
      tweaks: frob some comments, and reshuffle two fragments of code
      tweaks: frob two fragments of code, to be more readable
      tweaks: make a skipping condition more precise
      tweaks: remove an old fix that was made superfluous by a recent fix
      tweaks: remove a strangely placed warning
      tweaks: rename six symbols, to be more straightforward
      tweaks: reshuffle some code, and reduce the scope of a variable
      tweaks: reshuffle three conditions into a better order
      tweaks: rewrap and reindent a few lines
      tweaks: rewrap two lines, for esthetics
      tweaks: stop evaluating a rule when the match is offscreen to the right

Signed-off-by: Adolf Belka (ipfire) <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>