Remove required description from label_placement parameter (#1444)

Author: Meghan Jones

pygmt/src/contour.py

@@ -81,7 +81,10 @@ def contour(self, x=None, y=None, z=None, data=None, **kwargs):
     E : str
         Network information.
     label_placement : str
-        Placement of labels.
+        [**d**\|\ **f**\|\ **n**\|\ **l**\|\ **L**\|\ **x**\|\ **X**]\ *args*.
+        Control the placement of labels along the quoted lines. It supports
+        five controlling algorithms. See :gmt-docs:`contour.html#g` for
+        details.
     I : bool
         Color the triangles using CPT.
     triangular_mesh_pen : str

pygmt/src/grdcontour.py

@@ -77,9 +77,9 @@ def grdcontour(self, grid, **kwargs):
     label_placement : str
         [**d**\|\ **f**\|\ **n**\|\ **l**\|\ **L**\|\ **x**\|\ **X**]\
         *args*.
-        The required parameter controls the placement of labels along the
-        quoted lines. It supports five controlling algorithms. See
-        :gmt-docs:`grdcontour.html#g` for details.
+        Control the placement of labels along the quoted lines. It supports
+        five controlling algorithms. See :gmt-docs:`grdcontour.html#g` for
+        details.
     {U}
     {V}
     {W}