Figure.legend: Fix incorrect docstrings (#4753)

Co-authored-by: Yvonne Fröhlich <94163266+yvonnefroehlich@users.noreply.github.com>

Author: seisman

examples/tutorials/advanced/legends.py

@@ -21,12 +21,11 @@
 # :meth:`pygmt.Figure.vlines` as well as :meth:`pygmt.Figure.histogram`. Therefore the
 # ``label`` parameter has to be specified to state the desired text for the legend entry
 # (white spaces are supported). Here, we use :meth:`pygmt.Figure.plot`, exemplary. By
-# default, the legend is placed in the Upper Right corner with an offset of 0.1
-# centimeters in both x- and y-directions, and surrounded by a box with a white fill and
-# a 1-point thick, black, solid outline. The order of the legend entries (top to bottom)
-# is determine by the plotting order. Optionally, to adjust the legend, append different
-# modifiers to the string passed to ``label``. For a list of available modifiers see
-# :gmt-docs:`gmt.html#l-full`. To create a :doc:`multiple-column legend
+# default, the legend is placed in the Upper Right corner and surrounded by a box with a
+# white fill and a 1-point thick, black, solid outline. The order of the legend entries
+# (top to bottom) is determined by the plotting order. Optionally, to adjust the legend,
+# append different modifiers to the string passed to ``label``. For a list of available
+# modifiers see :gmt-docs:`gmt.html#l-full`. To create a :doc:`multiple-column legend
 # </gallery/embellishments/legend>` **+N** is used with the desired number of columns.
 
 fig = pygmt.Figure()

pygmt/src/legend.py

@@ -93,9 +93,11 @@ def legend(
         width. If height is given as percentage then height is recomputed as that
         fraction of the legend width (not plot height).
 
-        **Note:** Currently, the automatic height calculation only works when legend
+        **Note:** Currently, the automatic width calculation only works when legend
         codes **D**, **H**, **L**, **S**, or **V** are used and that the number of
-        symbol columns (**N**) is 1.
+        symbol columns (**N**) is 1. If height is zero or not given, GMT estimates it
+        based on the expected vertical extent of the items to be placed. A legend
+        containing paragraph text may require an explicit height.
     line_spacing
         The line-spacing factor between legend entries in units of the current font size
         [Default is 1.1].