Add docs references to plot_ppc docstring

[roshnaeem]

Add links to the related functions and classes to all the places where they are mentioned in the plot_ppc docstring.

Sample PR:

You can see https://github.com/arviz-devs/arviz/pull/1816 for the function, plot_autocorr.

⚠️ Always create a new branch for changes. Don't make any changes to the main branch.

Source File

Source file: https://github.com/arviz-devs/arviz/blob/main/arviz/plots/ppcplot.py

How to add links

Add the links in the docstring of doc. You can also check the docstring by going to the [source].

• Add links to the ArviZ functions and classes using Cross-referencing with Sphinx.
• Add links to the xarray functions and classes using Intersphinx.
• Add the rest of the external links using this syntax.

backend_kwargs

For adding backend_kwargs as they have been added in #1816, see Adding backend_kwargs guide.

See also section

Add the following functions in the "See also" section:

1. plot_bvp

See Adding "see also" section for more details.

Checking the preview of docs

For checking the preview of docs, you don't need t set up the project on your local machine. Just follow the checking the preview guide.

[sudojarvis]

I would like to work on this.