Fix focus bug when moving between outputs

When moving focus left or right to an adjacent output, only select the
first or last child in the new workspace if the workspace's layout is
horizontalish. If it's a verticalish layout, use the last focused
container.

sway/tree/layout.c

@@ -586,11 +586,19 @@ static struct sway_container *get_swayc_in_output_direction(
 	if (ws->children->length > 0) {
 		switch (dir) {
 		case MOVE_LEFT:
-			// get most right child of new output
+			if (ws->layout == L_HORIZ || ws->layout == L_TABBED) {
-			return ws->children->items[ws->children->length-1];
+				// get most right child of new output
+				return ws->children->items[ws->children->length-1];
+			} else {
+				return seat_get_focus_inactive(seat, ws);
+			}
 		case MOVE_RIGHT:
-			// get most left child of new output
+			if (ws->layout == L_HORIZ || ws->layout == L_TABBED) {
-			return ws->children->items[0];
+				// get most left child of new output
+				return ws->children->items[0];
+			} else {
+				return seat_get_focus_inactive(seat, ws);
+			}
 		case MOVE_UP:
 		case MOVE_DOWN: {
 			struct sway_container *focused =