Fix railroad so head, body args included in html

[schnorea]

Minor fix in the railroad diagram code. Output wasn't getting the railroad.css styling. Attempts to include using this

style = """ # css styling """
...
# PEG definitions
statement = ....
....
statement.create_diagram("railroad_diagram_demo.html", vertical=6, show_results_names=True, embed=True, head=style)

failed. railroad_diagram_demo.html had no styling added except for what was in the template.

Noticed that **kwargs weren't being passed through to the template.

Added **kwargs in for the fix.

[ptmcg]

Thanks for this. Could you send me a tiny example that I could use to create a test for this? (I'm not too expert in CSS.)

No need for another commit, just post a comment here. For the grammar, just use something simple like Word(alphas)[...].set_name("words") Not really interested in the diagram, just in verifying the use of **kwargs.