After a series of escapes, also <Shift+Meta+letter> should be recognized
as a command keystroke, not just <Meta+letter>.

This fixes https://savannah.gnu.org/bugs/?55442.

Bug existed since the ignoring of <Escape>s before a valid command
keystroke was introduced in version 3.0, commit ecc9211a.

When the user switches backups on later (with M-B in the ^O menu),
the specified folder should have been checked for validity.

This fixes https://savannah.gnu.org/bugs/?55423.

Bug existed since the check for a valid backup directory was introduced
in version 2.8.7, commit 751e7f0f.

Also, rename the remaining parameter and rename a variable.

Give the correct feedback in those cases and do not add an undo item.

This fixes both parts of https://savannah.gnu.org/bugs/?55396.

This makes the cutting and pasting keystrokes somewhat discoverable.

Act the same way for M-T and for zapping.

This addresses https://savannah.gnu.org/bugs/?55330.

Also, adjust the type of a parameter to 'size_t', as it is a
character index.

Use 'size_t' for character indexes, and 'ssize_t' for the threshold.

Having all the cutting and deleting functions together in one file
kind of makes sense.

The reduced file size should be stored not just when joining two lines
but also when simply a character in the middle of a line is deleted.

This fixes https://savannah.gnu.org/bugs/?55352.

Bug existed since version 2.5.0, commit 66e21416.

This fixes https://savannah.gnu.org/bugs/?55332.

All tested systems (FreeBSD, NetBSD, OpenBSD, Alpine, and Ubuntu)
support the GNU-style word boundaries (\< and \>), either natively
or through using the regex module from gnulib.

If this change breaks regexes containing \< or \> on your system,
please report a bug: https://savannah.gnu.org/bugs/?group=nano

This addresses https://savannah.gnu.org/bugs/?55207.

Also, for <Esc> <Esc> [, report that it is unbindable.

This fixes https://savannah.gnu.org/bugs/?55336.

And in the bargain add two missing equivalences.

And in the bargain it makes things clearer, because the name
cutbuffer_reset() is misleading.

The parameter was made redundant by David's overhaul of the
justification code.

Reuse the WAS_FINAL_LINE flag to signal a cut that added a magicline,
for both a marked cut and cut-to-eof.

This fixes https://savannah.gnu.org/bugs/?55305.

This allows multiple flags to be set, which will be needed for the
next commit.

It's not just about the numeric keypad, but about the interpretation
of all editing keys (arrows, Home, End, PageUp, PageDown, Insert, and
Delete), of the escape sequences that they produce.

When using --raw, ncurses does not catch and convert any mouse event,
and thus the coordinates of a mouse click would get inserted into the
buffer as seemingly random characters.  So, let --rawsequences override
and disable --mouse, to prevent the accidental entering of junk.

This fixes https://savannah.gnu.org/bugs/?55303.

To better describe what it does, and to have full contrast with the
--rebinddelete option: the latter can now be shortened to --rebind
without getting a conflict, and --rawsequences can be abbreviated
to simply --raw and still make sense.

And in the bargain get rid of a duplicate help-text entry for
either "Del" or "Bsp".

When the terminfo selected by TERM does not match the terminal and
the <Delete> key behaves the same as <Backspace> (deleting leftward)
or the <Backspace> key behaves the same as <Delete> (deleting without
moving the cursor), then using just -d or --rebinddelete should make
the deviant key behave correctly again without affecting the other.