Fix docs index for advanced tutorials (#1925)

Max Jones · web-flow · commit 589332bd1496 · 2022-05-11T23:29:05.000-04:00
diff --git a/examples/tutorials/advanced/grid_equalization.py b/examples/tutorials/advanced/grid_equalization.py
@@ -1,6 +1,6 @@
 """
 Performing grid histogram equalization
---------------------------------------
+======================================
 The :meth:`pygmt.grdhisteq.equalize_grid` function creates a grid using
 statistics based on a cumulative distribution function.
 """
