doc/dev: link to Dot User's Manual

Add a link to the Dot User's Manual for Graphviz diagrams.

Signed-off-by: Zac Dover <zac.dover@gmail.com>
(cherry picked from commit 249a4794afc01ae27314e55f87932f7492fecb4f)

diff --git a/doc/dev/documenting.rst b/doc/dev/documenting.rst
index 42bd56d06fed5754d55090445efaf1c1d5d810d1..c1a11890e6e4a638d85f0d24b26690f318b7d558 100644 (file)
--- a/doc/dev/documenting.rst
+++ b/doc/dev/documenting.rst
@@ -86,6 +86,10 @@ separate file, like this::
 
   .. graphviz:: myfile.dot
 
+See the `Dot User's Manual <https://www.graphviz.org/pdf/dotguide.pdf>`_ by
+Emden R. Gansner, Eleftherios Koutsofios, and Stephen North for examples of
+digraphs. This is especially useful if this is your first time encountering
+GraphViz.
 
 Ditaa
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