Fix: Move locator back to top level (Ultraplot#490)

* Move locator back to top level

* Black formatter

Author: cvanelteren

ultraplot/__init__.py

@@ -47,6 +47,9 @@
     "Colormap": ("constructor", "Colormap"),
     "Cycle": ("constructor", "Cycle"),
     "Norm": ("constructor", "Norm"),
+    "Locator": ("constructor", "Locator"),
+    "Scale": ("constructor", "Scale"),
+    "Formatter": ("constructor", "Formatter"),
 }