[markov_chains_II] Editorial Suggestions

[HumphreyYang]

Comments by @longye-tian

• [x] Introduce "accessible" from communicate (if it communicates with each other).
• [x] "We discussed uniqueness of stationary distributions our earlier lecture on Markov chains" -> We discussed uniqueness of stationary distributions in our earlier lecture on Markov chains.
• [x] Unifymathbb for indicator function.
• [x] "an initial." -> "an initial".
• [x] Fix capitalization of the subtitle.
• [x] Discussed before -> discussed in [add doc link].
• [x] 1 + np.arrange(ts_length) -> np.arrange(1, ts_length + 1).
• [x] Change the time length for the periodic chain.
• [x] Political institution mode -> political institution model.
• [x] Remove the alpha parameter for 33.3.4 graph and remove the figsize.
• [x] Add a seed for the mc.simulate (@longye-tian).
• [x] Delete https://intro.quantecon.org/markov_chains_II.html#expectations-of-geometric-sums.
• [x] Change the graph to the simple one in the exercise.

[longye-tian]

Hi Humphrey,

Thank you for update the suggestions!

I have updated the lecture following all the comments above.

I believe this issue can be closed.

Best, Longye