This kind of addresses https://savannah.gnu.org/bugs/?53310.

This fixes https://savannah.gnu.org/bugs/?53317

.
Reported-by: David Lawrence Ramsey <pooka109@gmail.com>

This fixes https://savannah.gnu.org/bugs/?53269

.
Reported-by: Ashish Kunwar <dorkerdevil280@gmail.com>

The leak was mistakenly introduced by commit dc3618a1
-- probably as a leftover of testing things.

And adjust the comments accordingly.

Help texts are shown without any line numbers, so the full width
of the screen should be used to display the text.

This fixes https://savannah.gnu.org/bugs/?53308.

Signed-off-by: Brand Huntsman <alpha@qzx.com>

First the two that add something (ADD, ENTER), then the three that
delete something (BACK, DEL, JOIN), and then the one that changes
something (REPLACE).  Then the SPLITs, CUT, PASTE, and INSERT, and
then the INDENTs and COMMENTs, when they exist.

For cuts, pastes, and inserts, the lines have already been renumbered;
for indents, comments, and replacements, the line numbers cannot have
changed.  (And anyway, variable 'f' is not set for those cases.)

Only when lines get split (ENTER) or fused together (JOIN) do the later
lines need to be renumbered.  This mirrors what is done for do_redo().

The 'f' variable is used only in the ADD, BACK, DEL, ENTER, JOIN, and
REPLACE undo/redo cases.  So, avoid making a somewhat costly call when
it is entirely superfluous.  Rearrange the undo types to make checking
for the above six types easier.

This fixes https://savannah.gnu.org/bugs/?53272.

On a Linux console, ^/ produces Backspace, making it unrebindable.

This fixes https://savannah.gnu.org/bugs/?53248.

It is not a problem to say that ^X closes the current buffer
even when nano is compiled without multibuffer support.

This assumes that all movement functions are located together,
starting with to_first_line() and ending with do_right().

This fixes https://savannah.gnu.org/bugs/?53195

.
Reported-by: Brand Huntsman <alpha@qzx.com>

As of commit c79fe1a1, the more readable ^/ has replaced ^_ as the
advertised shortcut for Go-To-Line -- color it too as valid.

To prevent getting kicked out of it.

This fixes https://savannah.gnu.org/bugs/?53234.

The implant() function itself cannot be bound to anything, so it
is not in the linked list of functions -- trying to find it would
lead to a NULL pointer, and thus to a segfault.

This fixes https://savannah.gnu.org/bugs/?53233.

Commit 0cf455bc introduced the typo.

And remove a detail that is untrue when 'set selectedcolor' is used.

This fixes https://savannah.gnu.org/bugs/?53225.

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.