This fixes https://savannah.gnu.org/bugs/?49058 reported by Rishabh Dave.

This fixes https://savannah.gnu.org/bugs/?49106.

Also, show in green only the ^ and M- combinations that are valid.

This fixes https://savannah.gnu.org/bugs/?49097

.
Signed-off-by: Rishabh Dave <rishabhddave@gmail.com>
Signed-off-by: Benno Schulenberg <bensberg@justemail.net>

This avoids https://savannah.gnu.org/bugs/?49298.

This fixes https://savannah.gnu.org/bugs/?47710
and fixes https://savannah.gnu.org/bugs/?49088.

Returning a zero would mean returning a ^Space -- the keycode that
by default is bound to the Next-Word function.  So, unbinding the
keys to which the modified Arrow keys are hard bound would cause
the latter ones to mysteriously jump to the next word.

This partially fixes https://savannah.gnu.org/bugs/?49058.

Meta keys should have a dash as second character, and apart from ^Space
and M-Space key names should be at most two or three characters long.

This fixes https://savannah.gnu.org/bugs/?44688

.
Reviewed-by: Benno Schulenberg <bensberg@justemail.net>
Signed-off-by: Rishabh Dave <rishabhddave@gmail.com>

This fixes https://savannah.gnu.org/bugs/?49086.

This fixes https://savannah.gnu.org/bugs/index.php?42189.

And also case-sensitive searches, backward searches, and searching again.

This lets users of braille displays find the selected item immediately.

This fulfills a request by Enrico Mioso.
See https://lists.gnu.org/archive/html/nano-devel/2016-09/msg00025.html.

And correct a comment: the key /does/ occur also in the tiny version.

The prompt from which the browser was invoked has already blanked it.

This fixes https://savannah.gnu.org/bugs/?48987.

This fixes https://savannah.gnu.org/bugs/?48988.

These keycodes have non-rebindable entries in the list of shortcuts, so
they will always be there -- no need for a function call to find them.