DOC: fix EX03 Errors for pandas.read_json

[erichxchen]

• Ref: DOC: fix EX03 errors in docstrings #56804

Fix these EX03 Errors for pandas.read_json

flake8 error: line 6, col 23: F821 undefined name '_'
flake8 error: line 8, col 23: F821 undefined name '_'
flake8 error: line 10, col 23: F821 undefined name '_'

[datapythonista]

Since we are already creating the dataframe and calling to_json I think it'd be better to save the dataframe to a StringIO object, display it so users can continue to see how the json looks like, and then make this work by reading the StringIO object. What do you think?

[datapythonista]

The CI wasn't working to validate those docstrings. It's now been fixed, and there are some errors here and in your other PR, can you have a look please?

[erichxchen]

The CI wasn't working to validate those docstrings. It's now been fixed, and there are some errors here and in your other PR, can you have a look please?

I am actually confused about why it still errored out when commented with # doctest: +SKIP and # noqa: E501 (also in another PR). I will dig into when I have more spare time.

[mroeschke]

Closed by #57025