DOCSP-48191 Add noindex to style guide

[stephmarie17]

Pull Request Process

Please read the
Style Guide Review Process
wiki page.

Contributors should take the following actions:

• Request a PR review in #docs-style-guide Slack channel.
• Add the Style Guide team reps as reviewers.
• If any reviewer requests changes, address them and request another review.
• When you receive PR review approvals from all the Style Guide team reps,
  they will merge the PR and notify you of the merge in the Slack channel.

Pull Request Description

JIRA URL: https://jira.mongodb.org/browse/DOCSP-48191

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[mongoKart]

LGTM