Trim a superfluous assert too.

Also avoid an unused-variable warning, and trim a useless assert.

It takes almost no code and is a useful little improvement over Pico.

File formats, appending and prepending, and backups are not available
when --enable-tiny is used, so prevent all relevant pieces of code from
getting compiled.  And correct two misspelled ENABLE_TINY to NANO_TINY.

And in the bargain avoid a duplicate call of strlenpt(prompt).

Because nothing gets reset to zero or to some initial value.

To avoid an ncurses hiccup (miscoloring) when running on musl.

This fixes https://savannah.gnu.org/bugs/?50787

.
Reported-by: Avi Halachmi <avihpit@yahoo.com>

The cursor needs to be placed in its proper spot in the edit window
/only/ when nano is about to accept input from the user and needs to
show where this input will go.

(This might cause a scrolling issue to appear, because reset_cursor()
does not just place the cursor, it also recomputes current_y, which
is used in several places to determine whether and how much to scroll.
If it so happens, we'll deal with that fallout later.)

Furthermore, change an item header into a question, swap two items,
and tweak the formatting a bit.

This also groups ^I and ^M together, and cutwordleft and cutwordright
(when they are bound).  It furthermore makes that less pairs are now
mixed and instead consist of either two Ctrl or two Meta combos.  In
short: it looks better in the default config.  The only sacrifice is
that Verbatim is now split off from the other "inserting" keys.

This fixes https://savannah.gnu.org/bugs/?47131.

When the user chooses not to open a file that some message refers to,
remove all messages for that file from the linting results, so the user
does not get asked about that same file again.

This fixes https://savannah.gnu.org/bugs/?47130.

Replace them by a single subtraction.

When UTF-8 is available, use actual arrows instead of untranslated words
to indicate the cursor keys in the search history, as is done elsewhere.

These functions are used only in the file in which they are declared,
and they are declared before they are used.

The interval 2013-2017 for the Free Software Foundation is valid
because in those years there were releases with changes by either
Chris or David, and the GNU maintainers guide advises to mention
a new year in all files of a package, not just in the ones that
actually changed, and be done with it for the rest of the year.

To make dynamic Home and End work properly when double-width characters
straddle a chunk boundary, use the spot where the cursor is really shown
instead of the "actual x" position of the current character, because the
latter might be on the preceding row.

This fixes https://savannah.gnu.org/bugs/?50737.

Also, use single quotes for rcfile options more consistently.

Also, M-A is far more mnemonic for setting the mark than ^6 or ^^,
so it's better to try and teach the user that.

Make nano recognize the escape sequences for Ctrl-Home, Ctrl-End,
Shift-Ctrl-Home, and Shift-Ctrl-End on xterm, rxvt, and Eterm.

On some terminal emulators, Ctrl+Home and Ctrl+End produce special
keycodes, distinct from plain Home and End.  Make the users of those
emulators (and of the Linux console) glad by making ^Home and ^End
do the obvious thing, and the combinations with Shift too.

When Enter is pressed while the cursor is exactly on the current
indent width, remove the blank characters on that line to avoid
creating a line that consists only of trailing whitespace.

(When Enter is pressed somewhere in the middle of the blanks,
however, the whitespace is preserved.)
Suggested-by: Florian Zeitz <florob@babelmonkeys.de>

When a multi-column character straddles a chunk boundary, and the
preferred column (placewewant) for the cursor is zero, cheat: show
the cursor not where the character starts but on the beginning of
the next row.  This makes the cursor move smoothly in the leftmost
column of the screen when using <Up> and <Down> and such, instead
of jumping around.

In this way the scrolling logic won't get confused and the screen
will scroll properly when stepping beyond the top or bottom row.

This fixes https://savannah.gnu.org/bugs/?50687.

This fixes https://savannah.gnu.org/bugs/?50741.

If we're using the bundled gnulib regex module, then assume REG_ENHANCED
is not supported (since gnulib doesn't support it).

This fixes https://savannah.gnu.org/bugs/?50714.

When UTF-8 is available, use actual arrows instead of untranslated words
to indicate the cursor keys.  This was already done for the combinations
with Ctrl but not yet for the plain cursor keys.