DOC: Styling guide lacks links to the referenced objects

[moi90]

Location of the documentation

https://pandas.pydata.org/pandas-docs/stable/user_guide/style.html

Documentation problem

The page lacks links to the referenced objects (DataFrame, Series, ... but most importantly Styler).

Suggested fix for documentation

Links should be included. This could either be done using raw reST cells (which looks not as nice in the downloadable notebook) or by inserting relative links into the markdown code (which breaks easily).

[attack68]

does #39720 address some of these items?

[attack68]

It creates links in the jupyter notebook that sphinx can parse. Such as:

Styling should be performed after the data in a DataFrame has been processed. 
The [Styler][styler] creates an HTML `<table>` and leverages CSS styling language to
 manipulate many parameters including colors, fonts, borders, background, etc. 
See [here][w3schools] for more information on styling HTML tables.
 This allows a lot of flexibility out of the box, and even enables web developers to 
integrate DataFrames into their exiting user interface designs.

The `DataFrame.style` attribute is a property that returns a [Styler][styler] object.
It has a `_repr_html_` method defined on it so they are rendered automatically in Jupyter Notebook.

[styler]: ../reference/api/pandas.io.formats.style.Styler.rst
[w3schools]: https://www.w3schools.com/html/html_tables.asp

[moi90]

@attack68 Yes, I think #39720 resolves this issue. 👍