Add :arglists metadata in defplot

[glts]

When using Huri in Gorilla REPL, completion for the plot functions shows
the gensym argument names, which are a bit difficult to parse,
especially for people who are now and exploring the API.

In this change I propose adding :arglists metadata to make this
better.

Doc before:

huri.plot/scatter-plot
([df__20154__auto__] [options__20146__auto__ df__20147__auto__] [x y df__20148__auto__] [x y options__20155__auto__ df__20154__auto__])

And after:

huri.plot/scatter-plot
([df] [options df] [x y df] [x y options df])

Thank you for your consideration!