bindings: rename constupdate to constantshow, cuttoend to cutfromcursor

This makes the names of these bindable functions equal to the names of
their corresponding options -- like for all the other toggles that have
a corresponding option.

doc/nano.texi

@@ -1347,7 +1347,7 @@ Goes to the last file when using the file browser (reading or writing files).
 @item nohelp
 Toggles the presence of the two-line list of key bindings at the bottom of the screen.
 
-@item constupdate
+@item constantshow
 Toggles the constant display of the current line, column, and character positions.
 
 @item morespace
@@ -1374,7 +1374,7 @@ Toggles the smartness of the Home key.
 @item autoindent
 Toggles whether new lines will contain the same amount of whitespace as the preceding line.
 
-@item cuttoend
+@item cutfromcursor
 Toggles whether cutting text will cut the whole line or just from the current cursor
 position to the end of the line.
 

doc/nanorc.5

@@ -703,7 +703,7 @@ Goes to the last file when using the file browser (reading or writing files).
 .B nohelp
 Toggles the presence of the two-line list of key bindings at the bottom of the screen.
 .TP
-.B constupdate
+.B constantshow
 Toggles the constant display of the current line, column, and character positions.
 .TP
 .B morespace
@@ -730,7 +730,7 @@ Toggles the smartness of the Home key.
 .B autoindent
 Toggles whether new lines will contain the same amount of whitespace as the preceding line.
 .TP
-.B cuttoend
+.B cutfromcursor
 Toggles whether cutting text will cut the whole line or just from the current cursor
 position to the end of the line.
 .TP

src/global.c

@@ -1659,7 +1659,8 @@ sc *strtosc(const char *input)
 		s->func = do_toggle_void;
 		if (!strcasecmp(input, "nohelp"))
 			s->toggle = NO_HELP;
-		else if (!strcasecmp(input, "constupdate"))
+		else if (!strcasecmp(input, "constantshow") ||
+				 !strcasecmp(input, "constupdate"))  /* Deprecated.  Remove end of 2018. */
 			s->toggle = CONSTANT_SHOW;
 		else if (!strcasecmp(input, "morespace"))
 			s->toggle = MORE_SPACE;
@@ -1681,7 +1682,8 @@ sc *strtosc(const char *input)
 			s->toggle = SMART_HOME;
 		else if (!strcasecmp(input, "autoindent"))
 			s->toggle = AUTOINDENT;
-		else if (!strcasecmp(input, "cuttoend"))
+		else if (!strcasecmp(input, "cutfromcursor") ||
+				 !strcasecmp(input, "cuttoend"))  /* Deprecated.  Remove end of 2018. */
 			s->toggle = CUT_FROM_CURSOR;
 #ifdef ENABLE_WRAPPING
 		else if (!strcasecmp(input, "nowrap"))