[v1.1] emacs: remove annoying paper terminal feature for ^U (kill)

Quoth the manual:

>      kill      (User defined kill character as defined by the
>                stty(1) command, usually ^U.) Kill the entire
>                current line.  If two kill characters are entered
>                in succession, all kill characters from then on
>                cause a line feed (useful when using paper
>                terminals).  A subsequent pair of kill characters
>                undoes this change.

That latter feature has annoyed me long enough. It's too common to
press ^U twice accidentally. Also, paper terminals? I didn't know
ksh93 existed in the 1970s :-)

ANNOUNCE

@@ -14,6 +14,9 @@ New command line editor features:
   The arrow-up and arrow-down keys now act like PageUp and PageDown, unless
   the new --arrowkeysearch option is turned off (see below).
 
+- In the emacs line editor, pressing ^U (kill) twice no longer causes further
+  ^U presses to start a new line (this was a feature for paper terminals).
+
 New shell language features:
 
 - The 'time' reserved word now outputs timings in a precision of 3 digits

NEWS

@@ -8,6 +8,9 @@ Uppercase BUG_* IDs are shell bug IDs as used by the Modernish shell library.
   corresponding closing parentheses and enclosed within a compound command
   failed to throw a syntax error and could cause the shell to crash.
 
+- [v1.1] In emacs mode, pressing ^U (kill) twice no longer causes further
+  ^U presses to start a new line (this was a feature for paper terminals).
+
 2024-07-20:
 
 - Fixed a regression where a broken pipe signal (SIGPIPE), when occurring in

src/cmd/ksh93/edit/emacs.c

@@ -113,11 +113,6 @@ typedef struct _emacs_
 	char	lastdraw;	/* last update type */
 	int	offset;		/* Screen offset */
 	char	ehist;		/* hist handling required */
-	enum
-	{
-		CRT=0,	/* Crt terminal */
-		PAPER	/* Paper terminal */
-	} terminal;
 	Histloc_t _location;
 	int	prevdirection; 
 	Edit_t	*ed;	/* pointer to edit data */
@@ -594,28 +589,6 @@ int ed_emacsread(void *context, int fd,char *buff,int scend, int reedit)
 #endif /* ESH_KAPPEND */
 			out[i] = 0;
 			draw(ep,UPDATE);
-			if (c == KILLCHAR)
-			{
-				if (ep->terminal == PAPER)
-				{
-					putchar(ep->ed,'\n');
-					ed_putstring(ep->ed,Prompt);
-				}
-				c = ed_getchar(ep->ed,0);
-				if (c != usrkill)
-				{
-					ed_ungetchar(ep->ed,c);
-					continue;
-				}
-				if (ep->terminal == PAPER)
-					ep->terminal = CRT;
-				else
-				{
-					ep->terminal = PAPER;
-					putchar(ep->ed,'\n');
-					ed_putstring(ep->ed,Prompt);
-				}
-			}
 			continue;
 		case cntl('L'):
 			putchar(ep->ed,'\n');

src/cmd/ksh93/sh.1

@@ -5322,14 +5322,6 @@ by the
 command, usually
 .BR ^U .)
 Kill the entire current line.
-If two
-.I kill
-characters are entered in succession, all
-kill characters from then on cause a line feed
-(useful when using paper terminals).
-A subsequent pair of
-.I kill
-characters undoes this change.
 .TP 10
 .BI ^Y
 Restore last item removed from line. (Yank item back to the line.)