bindings: remove backup and new-buffer toggles (M-B, M-F) from main menu

These are available in the menus where they are relevant: the Write-Out
and the Insert menu, respectively.  Having them duplicated in the main
menu is inconsistent and eats precious keystrokes.  (Sorry, Chris.)

doc/nano.texi

@@ -596,15 +596,9 @@ The following global toggles are available:
 
 @table @code
 
-@item Backup Files
-@kbd{Meta-B} toggles the @option{-B} (@option{--backup}) command-line option.
-
 @item Constant Cursor Position Display
 @kbd{Meta-C} toggles the @option{-c} (@option{--constantshow}) command-line option.
 
-@item Multiple File Buffers
-@kbd{Meta-F} toggles the @option{-F} (@option{--multibuffer}) command-line option.
-
 @item Smart Home Key
 @kbd{Meta-H} toggles the @option{-A} (@option{--smarthome}) command-line option.
 
@@ -1420,13 +1414,6 @@ Toggles whether long lines will be hard-wrapped to the next line.
 @item tabstospaces
 Toggles whether typed tabs will be converted to spaces.
 
-@item backupfile
-Toggles whether a backup will be made of the file to be edited.
-
-@item multibuffer
-Toggles whether a file is inserted into the current buffer
-or read into a new buffer.
-
 @item mouse
 Toggles mouse support.
 

doc/nanorc.5

@@ -777,13 +777,6 @@ Toggles whether long lines will be hard-wrapped to the next line.
 .B tabstospaces
 Toggles whether typed tabs will be converted to spaces.
 .TP
-.B backupfile
-Toggles whether a backup will be made of the file being edited.
-.TP
-.B multibuffer
-Toggles whether a file is inserted into the current buffer
-or read into a new buffer.
-.TP
 .B mouse
 Toggles mouse support.
 .TP

src/global.c

@@ -1255,10 +1255,6 @@ void shortcut_init(void)
 	add_to_sclist(MMAIN, "M-O", 0, do_toggle_void, TABS_TO_SPACES);
 
 	/* Group of "Peripheral-feature" toggles. */
-	add_to_sclist(MMAIN, "M-B", 0, do_toggle_void, BACKUP_FILE);
-#ifdef ENABLE_MULTIBUFFER
-	add_to_sclist(MMAIN, "M-F", 0, do_toggle_void, MULTIBUFFER);
-#endif
 #ifdef ENABLE_MOUSE
 	add_to_sclist(MMAIN, "M-M", 0, do_toggle_void, USE_MOUSE);
 #endif
@@ -1413,10 +1409,6 @@ const char *flagtostr(int flag)
 			return N_("Hard wrapping of overlong lines");
 		case TABS_TO_SPACES:
 			return N_("Conversion of typed tabs to spaces");
-		case BACKUP_FILE:
-			return N_("Backup files");
-		case MULTIBUFFER:
-			return N_("Reading file into separate buffer");
 		case USE_MOUSE:
 			return N_("Mouse support");
 		case SUSPEND:
@@ -1681,12 +1673,6 @@ sc *strtosc(const char *input)
 #endif
 		else if (!strcasecmp(input, "tabstospaces"))
 			s->toggle = TABS_TO_SPACES;
-		else if (!strcasecmp(input, "backupfile"))
-			s->toggle = BACKUP_FILE;
-#ifdef ENABLE_MULTIBUFFER
-		else if (!strcasecmp(input, "multibuffer"))
-			s->toggle = MULTIBUFFER;
-#endif
 #ifdef ENABLE_MOUSE
 		else if (!strcasecmp(input, "mouse"))
 			s->toggle = USE_MOUSE;