nano: Update to 2.7.3

nano: Update to 2.7.3

Sorry, they did it again...:

For details see:
https://www.nano-editor.org/news.php

"GNU nano 2.7.3 "Ontbijtkoek" wipes away a handful of bugs:
your editor is now able to handle filenames that contain
newlines, avoids a brief flash of color when switching
between buffers that are governed by different syntaxes,
makes the Shift+Ctrl+Arrow keys select text again on a
Linux console, is more resistant against malformations
in the positionlog file, and does not crash when ^C is
typed on systems where it produces the code KEY_CANCEL.
Oh, and it no longer mistakenly warns about editing an
unlocked file just after saving a new one.  That's it.
Tastes great with thick butter."

Best,
Matthias

Signed-off-by: Matthias Fischer <matthias.fischer@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>