Remap ^S and ^Q.

The replacement keys are:

^J - toggle du mode
^Y - quit

The change is done because ^S, ^Q keybinds are lost in the following case:
- start nnn
- navigate to a different directory
- spawn a shell
- exit the shell

The issue happens only with the 'special' keybinds like ^S, ^Q, ^Z... which get
their original shell interpretation back.

So we are replacing these 2 keybinds with 2 'non-special' combinations.

README.md

@@ -237,7 +237,7 @@ optional arguments:
               n | Create new
              ^R | Rename entry
               s | Toggle sort by size
-          S, ^S | Toggle du mode
+          S, ^J | Toggle du mode
               t | Toggle sort by mtime
               ! | Spawn SHELL in dir
               e | Edit entry in EDITOR
@@ -249,7 +249,7 @@ optional arguments:
              ^L | Redraw, clear prompt
               ? | Help, settings
               Q | Quit and cd
-          q, ^Q | Quit
+          q, ^Y | Quit
 ```
 
 Help & settings, file details, media info and archive listing are shown in the PAGER. Please use the PAGER-specific keys in these screens.

nnn.1

@@ -84,7 +84,7 @@ Create a new file or directory
 Rename selected entry
 .It Ic s
 Toggle sort by file size
-.It Ic S, ^S
+.It Ic S, ^J
 Toggle disk usage analyzer mode
 .It Ic t
 Toggle sort by time modified
@@ -108,7 +108,7 @@ Force a redraw, clear rename or filter prompt
 Toggle help and settings screen
 .It Ic Q
 Quit and change directory
-.It Ic q, ^Q
+.It Ic q, ^Y
 Quit
 .El
 .Pp

nnn.c

@@ -988,9 +988,9 @@ filterentries(char *path)
 			case CONTROL('O'): // fallthrough
 			case CONTROL('B'): // fallthrough
 			case CONTROL('V'): // fallthrough
-			case CONTROL('S'): // fallthrough
+			case CONTROL('J'): // fallthrough
 			case CONTROL('X'): // fallthrough
-			case CONTROL('Q'):
+			case CONTROL('Y'):
 				goto end;
 			default:
 				/* Reset cur in case it's a repeat search */
@@ -1717,7 +1717,7 @@ show_help(char *path)
 	     "en | Create new\n"
 	    "d^R | Rename entry\n"
 	     "es | Toggle sort by size\n"
-	 "aS, ^S | Toggle du mode\n"
+	 "aS, ^J | Toggle du mode\n"
 	     "et | Toggle sort by mtime\n"
 	     "e! | Spawn SHELL in dir\n"
 	     "ee | Edit entry in EDITOR\n"
@@ -1729,7 +1729,7 @@ show_help(char *path)
 	    "d^L | Redraw, clear prompt\n"
 	     "e? | Help, settings\n"
 	     "eQ | Quit and cd\n"
-	 "aq, ^Q | Quit\n\n");
+	 "aq, ^Y | Quit\n\n");
 
 	if (fd == -1)
 		return -1;

nnn.h

@@ -137,7 +137,7 @@ static struct key bindings[] = {
 	{ 's',            SEL_FSIZE,     "",     "" },
 	/* Sort by total block count including dir contents */
 	{ 'S',            SEL_BSIZE,     "",     "" },
-	{ CONTROL('S'),   SEL_BSIZE,     "",     "" },
+	{ CONTROL('J'),   SEL_BSIZE,     "",     "" },
 	/* Toggle sort by time */
 	{ 't',            SEL_MTIME,     "",     "" },
 	/* Redraw window */
@@ -163,5 +163,5 @@ static struct key bindings[] = {
 	{ 'Q',            SEL_CDQUIT,    "",     "" },
 	/* Quit */
 	{ 'q',            SEL_QUIT,      "",     "" },
-	{ CONTROL('Q'),   SEL_QUIT,      "",     "" },
+	{ CONTROL('Y'),   SEL_QUIT,      "",     "" },
 };