DOC: Add code-formatting and cross-reference links to read_csv docs…

…tring (#53735)

* apply appropriate code-formatting to `read_csv` docstring using backticks

* escape curly braces for `dict` examples

* fix formatting under `delim_whitespace` so that tab character appears properly

* fix formatting issue in read_csv description for dtype_backend

* test linking for :class:`~pandas.DataFrame`

* add spinx references to pandas classes and functions

* remove code formatting from initial parameter description lines in read_csv

* replaced "default None" with "optional" in read_csv docstring

* add additional code formatting changes to read_csv after review

* shorten docstring lines to 88 characters max

* fix formatting causing docstring error

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Co-authored-by: tpaxman <[email protected]>