indenting: keep affecting last line of marked region if it was at first

When unindenting/uncommenting affected the bottom line of the marked
region, keep affecting this line also during subsequent consecutive
indenting/commenting.

This fixes https://savannah.gnu.org/bugs/?52718.

src/global.c

@@ -67,7 +67,9 @@ char *title = NULL;
 
 bool more_than_one = FALSE;
 	/* Whether more than one buffer is or has been open. */
-
+bool also_the_last = FALSE;
+	/* Whether indenting/commenting should include the last line of
+	 * the marked region. */
 int didfind = 0;
 	/* Whether the last search found something. */
 

src/nano.c

@@ -1698,13 +1698,16 @@ int do_input(bool allow_funcs)
 	    /* Execute the function of the shortcut. */
 	    s->scfunc();
 #ifndef NANO_TINY
-	    /* If Shiftless movement occurred, discard a soft mark. */
-	    if (!shift_held && openfile->mark &&
-				openfile->kind_of_mark == SOFTMARK &&
-				(openfile->current_x != was_x ||
-				openfile->current != was_current)) {
-		openfile->mark = NULL;
-		refresh_needed = TRUE;
+	    /* When the marked region changes without Shift being held,
+	     * discard a soft mark.  And when the marked region covers a
+	     * different set of lines, reset  the "last line too" flag. */
+	    if (openfile->mark && (openfile->current != was_current ||
+					openfile->current_x != was_x)) {
+		if (!shift_held && openfile->kind_of_mark == SOFTMARK) {
+		    openfile->mark = NULL;
+		    refresh_needed = TRUE;
+		} else if (openfile->current != was_current)
+		    also_the_last = FALSE;
 	    }
 #endif
 #ifdef ENABLE_WRAPPING

src/proto.h

@@ -54,6 +54,8 @@ extern char *title;
 
 extern bool more_than_one;
 
+extern bool also_the_last;
+
 extern int didfind;
 
 extern int controlleft;

src/utils.c

@@ -541,8 +541,10 @@ void get_range(const filestruct **top, const filestruct **bot)
 
 	mark_order(top, &top_x, bot, &bot_x, NULL);
 
-	if (bot_x == 0 && *bot != *top)
+	if (bot_x == 0 && *bot != *top && !also_the_last)
 	    *bot = (*bot)->prev;
+	else
+	    also_the_last = TRUE;
     }
 }