Add reference landing page and update link

[DaveDuggins]

Motivation

Need a landing page for References content block.

Modifications

Added reference landing page with links to reference resources.

Verifying this change

• Make sure that the change passes the CI checks.

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

[momo-jun]

Hi @DaveDuggins, fyi - I've fixed the following syntax/style issues, including:

1. Use double quotes " instead of “ for the sidebar_label field in the reference-landing.md file.
2. Use --- instead of - following the sidebar_label field in the reference-landing.md file.
3. Add reference-landing to the left navigation by updating the sidebars.json file.

The preview cannot succeed due to issues 1&2. Now it works as follows:

Another suggestion is - Create a separate PR in your forked repo for a new batch of changes. Currently, you are using the master branch of your repo as usual, so there is a long list of commit history, which is not necessary.