nano: update to 2.9.1

Changes between v2.9.0 and v2.9.1:
Benno Schulenberg (21):
    build: fix compilation with --disable-browser --disable-tabcomp
    bump version numbers and add a news item for the 2.9.1 release
    files: always update the stat info when the entire file is written
    files: save the marked region only when we've prompted for a file name
    gnulib: update to its current upstream state
    history: create the path '~/.local/share/' when it is needed
    history: make nano's state directory accessible for the user only
    history: save the positions file also when a record was deleted
    input: make the macro key discoverable by giving feedback when undefined
    linting: switch the mark off when the linter starts
    po: update translations and regenerate POT file and PO files
    selecting: do not cancel the softmark when the cursor is not moved
    selecting: let a justification cancel a softmark
    syntax: adjust the magic strings for the changes since file-5.10
    tweaks: adjust indentation after previous change
    tweaks: elide the 'mark_set' boolean -- the 'mark' pointer is enough
    tweaks: rename, rewrap, and reshuffle some stuff, and frob some comments
    tweaks: reshuffle a couple of lines, and frob a comment or two
    tweaks: reshuffle a couple of lines, to put similar things together
    undo: clear the Modified state when the very first edit is undone
    undo: discarding the stack does not always lose information

(schwarz)