Fix rollover bug (#747)

* Fix rollover bug

Fixes #743

* Snap to edges in no rollover multiline scroll mode

* Style fix

src/nnn.c

@@ -5973,14 +5973,20 @@ nochange:
 #if NCURSES_MOUSE_VERSION > 1
 			/* Scroll up */
 			if (event.bstate == BUTTON4_PRESSED && ndents && (cfg.rollover || cur)) {
-				move_cursor((cur + ndents - scroll_lines) % ndents, 0);
+				if (!cfg.rollover && cur < scroll_lines)
+					move_cursor(0,0);
+				else
+					move_cursor((cur + ndents - scroll_lines) % ndents, 0);
 				break;
 			}
 
 			/* Scroll down */
 			if (event.bstate == BUTTON5_PRESSED && ndents
 			    && (cfg.rollover || (cur != ndents - 1))) {
-				move_cursor((cur + scroll_lines) % ndents, 0);
+				if (!cfg.rollover && cur >= ndents - scroll_lines)
+					move_cursor(ndents-1, 0);
+				else
+					move_cursor((cur + scroll_lines) % ndents, 0);
 				break;
 			}
 #endif