Fix focus mode_toggle from a child of a floating container

Also fixes a crash when unfloating a window. It needs to add it back to
the tiling tree as a sibling rather than a child, because the reference
container might be a view.

sway/commands/focus.c

@@ -35,6 +35,15 @@ static struct cmd_results *focus_mode(struct sway_container *con,
 		struct sway_seat *seat, bool floating) {
 	struct sway_container *ws = con->type == C_WORKSPACE ?
 		con : container_parent(con, C_WORKSPACE);
+
+	// If the container is in a floating split container,
+	// operate on the split container instead of the child.
+	if (container_is_floating_or_child(con)) {
+		while (con->parent->layout != L_FLOATING) {
+			con = con->parent;
+		}
+	}
+
 	struct sway_container *new_focus = NULL;
 	if (floating) {
 		new_focus = seat_get_focus_inactive(seat, ws->sway_workspace->floating);
@@ -99,7 +108,7 @@ struct cmd_results *cmd_focus(int argc, char **argv) {
 	} else if (strcmp(argv[0], "tiling") == 0) {
 		return focus_mode(con, seat, false);
 	} else if (strcmp(argv[0], "mode_toggle") == 0) {
-		return focus_mode(con, seat, !container_is_floating(con));
+		return focus_mode(con, seat, !container_is_floating_or_child(con));
 	}
 
 	if (strcmp(argv[0], "output") == 0) {

sway/tree/container.c

@@ -1033,7 +1033,7 @@ void container_set_floating(struct sway_container *container, bool enable) {
 		struct sway_container *sibling =
 			seat_get_focus_inactive_tiling(seat, workspace);
 		container_remove_child(container);
-		container_add_child(sibling, container);
+		container_add_sibling(sibling, container);
 		container->width = container->parent->width;
 		container->height = container->parent->height;
 		if (container->type == C_VIEW) {