FIX: spell warn_external correctly

tacaswell · timhoffm · web-flow · commit 4cd95eeda3a3 · 2021-01-22T15:13:27.000-05:00
Co-authored-by: Tim Hoffmann &lt;2836374+timhoffm@users.noreply.github.com&gt;
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -4521,7 +4521,7 @@ def scatter(self, x, y, s=None, c=None, marker=None, cmap=None, norm=None,
             marker_obj.get_transform())
         if not marker_obj.is_filled():
             if orig_edgecolor is not None:
-                _api._warn_external(
+                _api.warn_external(
                     f"You passed a edgecolor/edgecolors ({orig_edgecolor!r}) "
                     f"for an unfilled marker ({marker!r}).  Matplotlib is "
                     "ignoring the edgecolor in favor of the facecolor.  This "
