fix(readme): added chain + fixed hop malformat

[dess890]

@silkspace
do you know where I can find anything on predicates to fill it out?
re: #530

[lmeyerov]

@dess890 you can see the entries here: https://github.com/graphistry/pygraphistry/tree/master/graphistry/compute/predicates

weirdly:

• they do get listed here: https://pygraphistry.readthedocs.io/en/latest/graphistry.compute.predicates.html
  • ... no examples
  • ... and weird nav bar listing name+position from a table of contents perspective
• but fully empty when listed in the main area: https://pygraphistry.readthedocs.io/en/latest/graphistry.compute.html#predicates

for usage, it's generally something like

from graphistry import n, e, is_in

g2 = g1.chain([
  n({
    'k1': 'v',
     'k2': is_in(['a', 'b', 'c'])
  }),
  e(),
  n(),
  ...
])

Getting a quick description + example for each predicate would help, especially more interesting args. They are, by design, exact API matches to the pandas tabular equivalents they pass through to.

[lmeyerov]

@dess890 just checking in here, saw this was dangling

[dess890]

@aucahuasi realizing this just needs a review whenever you get the chance