docs: observer utilities PTL-1697

[Gareth-Spencer-Genesis]

ATTENTION! NEW DOCS STRUCTURE
FOR THE NEXT THREE WEEKS, ONLY BRANCH FROM new-docs-structure
OTHERWISE, WAIT UNTIL THE NEW STRUCTURE HAS BEEN RELEASED

• Please check the internal contributions guide for details

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Thank you for contributing to the documentation.

Do the changes you have made apply to both Current and Previous versions?
No

Have you done a trial build to check all new or changed links?
Yes

Is there anything else you would like us to know?
No

This week's exciting advice from the style guide

• Write your headings in sentence case:

  • A good example
    This is a correct heading.
  • A Bad Example
    This is not a correct heading.