Revert "Gallery example "choropleth map": Add code block separator "# %%" (#2805)"

This reverts commit 6ae2072.

Author: seisman

examples/gallery/maps/choropleth_map.py

@@ -14,7 +14,6 @@
 parameter as shown in the example below.
 """
 
-# %%
 import geopandas as gpd
 import pygmt