Docstrings: Links to the aesthetics.html page and notes for layer_key…

…() (#1145)

* Docstrings: Add images with available point shapes and line types.

* Docstrings: Replace images with point shapes and line types by links to the docs.

* Docstrings: Updates for layer_key() function.

python-package/lets_plot/bistro/qq.py

@@ -59,6 +59,7 @@ def qq_plot(data=None, sample=None, *, x=None, y=None,
         Size of the points.
     shape : int
         Shape of the points, an integer from 0 to 25.
+        For more info see https://lets-plot.org/python/pages/aesthetics.html#point-shapes.
     line_color : str, default='#FF0000'
         Color of the fitting line.
     line_size : float, default=0.75
@@ -67,6 +68,7 @@ def qq_plot(data=None, sample=None, *, x=None, y=None,
         Type of the fitting line.
         Codes and names: 0 = 'blank', 1 = 'solid', 2 = 'dashed',
         3 = 'dotted', 4 = 'dotdash', 5 = 'longdash', 6 = 'twodash'.
+        For more info see https://lets-plot.org/python/pages/aesthetics.html#line-types.
 
     Returns
     -------

python-package/lets_plot/bistro/waterfall.py

@@ -51,6 +51,7 @@ def waterfall_plot(data, x, y, *,
         Type of the box boundary lines.
         Codes and names: 0 = 'blank', 1 = 'solid', 2 = 'dashed',
         3 = 'dotted', 4 = 'dotdash', 5 = 'longdash', 6 = 'twodash'.
+        For more info see https://lets-plot.org/python/pages/aesthetics.html#line-types.
     width : float, default=0.9
         Width of the boxes. Typically range between 0 and 1.
         Values that are greater than 1 lead to overlapping of the boxes.