Intro "2. Create a contour map": Correct explanation of "pen" paramet…

…er (#2705)

examples/get_started/02_contour_map.py

@@ -87,9 +87,9 @@
 # ``annotation`` parameter annotates the contour lines corresponding to the
 # given interval (in this case, 1,000 meters) with the related values, here
 # elevation or bathymetry. By default, these contour lines are drawn thicker.
-# Optionally, the appearance (thickness, color, style) of the contour lines
-# can be adjusted by specifying a desired ``pen``, which then applies to all
-# contour lines.
+# Optionally, the appearance (thickness, color, style) of the annotated and
+# the not-annotated contour lines can be adjusted (separately) by specifying
+# the desired ``pen``.
 
 fig = pygmt.Figure()
 fig.grdimage(grid=grid, frame="a", projection="M10c", cmap="oleron")