DOCS-1131 - Intel 471 update

[jpipkin1]

Purpose of this pull request

This pull request adds a release note and makes updates to this article:
https://help.sumologic.com/docs/security/threat-intelligence/threat-intelligence-vendor-switch/

It also changes instances of "Intel471" to "Intel 471".

Select the type of change

• Minor Changes - Typos, formatting, slight revisions
• Update Content - Revisions, updating sections
• New Content - New features, sections, pages, tutorials
• Site and Tools - .clabot, version updates, maintenance, dependencies, new packages for the site (Docusaurus, Gatsby, React, etc.)

Ticket (if applicable)

DOCS-1131