Update whats_new_in_3_0_0.rst (pyparsing#258)

retsyo · web-flow · commit 32ac0bf9837f · 2021-01-03T16:36:45.000-06:00
since `pip install railroad` install anthor package, I think it is better to point out the corrected one.
diff --git a/docs/whats_new_in_3_0_0.rst b/docs/whats_new_in_3_0_0.rst
@@ -20,7 +20,8 @@ New Features
 Railroad diagramming
 --------------------
 An excellent new enhancement is the new railroad diagram
-generator for documenting pyparsing parsers::
+generator for documenting pyparsing parsers. You need to install
+`Railroad-Diagram Generator package` https://pypi.org/project/railroad-diagrams/ to test this example::
 
     import pyparsing as pp
 
