Instead of always calling sctofunc(), it is now only called when
in view mode OR when (after the keystroke's function has been run)
no need for a refresh has been established yet.

A shortcut's function must be among the existing ones, otherwise
nano's code is fundamentally broken.

Commit bb667beb removed do_gotolinecolumn_void() from the MWHEREIS
menu (replacing it with the empty flip_goto() function), so there
is no longer any need to check for this one special case.

A shortcut's function can never be NULL.

It is only ever set and never referenced.

Exclude the confusing, pleonastic 'sc' abbreviation from their names.

The new option 'set errorcolor' allows the user to specify the color
combination for the status bar when an error message is displayed.

This fixes https://savannah.gnu.org/bugs/?53188

.
Reported-by: Ken Tyler <kent@werple.net.au>

The slash is easier to read than the underscore (which almost
disappears at the bottom of the screen), and easier to type
(no Shift needed on a US keyboard), and it kind of harmonizes
with the ^\ for Replace and the M-/ for End-of-buffer.

See the discussion on the mailing list:
https://lists.gnu.org/archive/html/nano-devel/2018-01/msg00022.html
https://lists.gnu.org/archive/html/nano-devel/2018-02/msg00090.html

Signed-off-by: Tom Levy <tomlevy93@gmail.com>

When using --smooth or 'set smooth', the screen should scroll the
minimum amount needed to get the cursor back into view.  (The only
exceptions are search, undo, and redo -- when there the cursor goes
offscreen, the cursor line is centered.)

This change brings the behavior of pressing <Enter> on the bottom
row into line with, for example, pasting a single line.  See also
http://lists.gnu.org/archive/html/nano-devel/2018-02/msg00027.html.

This fixes https://savannah.gnu.org/bugs/?53157.

And when configured with --enable-tiny --enable-nanorc.

The different color will make the name stand out, as it should, instead
of looking the same as all the regex strings.

When 'refresh_needed' is already TRUE, there is no need any more
to check whether it should be set.

[Those first two calls are leftovers from before the time that
reset_multis() morphed into check_the_multis().]

This fixes https://savannah.gnu.org/bugs/?53089.

When characters are added via Verbatim Input or by pressing <Tab>,
the prepend flag should be retained, just like when characters are
typed directly.

This fixes https://savannah.gnu.org/bugs/?52956.

This fixes https://savannah.gnu.org/bugs/?53088.

When copying a string, source and destination may not be equal --
complain loudly when they are, instead of failing to free memory.

Also, instead of freeing the destination string and then allocating
it afresh, just reallocate it -- that should be slightly quicker.

When doing for example: ^W xx ^R ^C ^W, the "xx" would again be shown
after the prompt.  This is wrong -- when starting a new search, the
current answer should be empty.
Reported-by: Marco Diego Aurélio Mesquita <marcodiegomesquita@gmail.com>

Instead of weaving back and forth between do_search()/do_replace() and
search_init() every time that one of the options is toggled, just keep
looping in the latter function until the user presses <Enter>.

The weaving for the do_gotolinecolumn() function remains, but is
shortened to involve only search_init().

This fixes https://savannah.gnu.org/bugs/?53062.

Suggested-by: Mike Frysinger <vapier@gentoo.org>

This addresses https://savannah.gnu.org/bugs/?48992.

In this way a single keystroke can produce a fragment of text or a
series of commands, or a mix of the two.  It is like a prerecorded
macro.

This fulfills https://savannah.gnu.org/bugs/?52931.

This brings it in line with the other three "flip" toggles.