Document "Zigbee Groups" in ZHA integration

[Hedda]

Proposed change

Add initial documentation for "Zigbee Groups" in the ZHA integration (which was missing documentation about "Zigbee Group").

Type of change

• Spelling, grammar or other readability improvements (current branch).
• Adjusted missing or incorrect information in the current documentation (current branch).
• Added documentation for a new integration I'm adding to Home Assistant (next branch).
  • I've opened up a PR to add logo's and icons in Brands repository.
• Added documentation for a new feature I'm adding to Home Assistant (next branch).
• Removed stale or deprecated documentation.

Additional information

• Link to parent pull request in the codebase:
• Link to parent pull request in the Brands repository:
• This PR fixes or closes issue: fixes #

Checklist

• This PR uses the correct branch, based on one of the following:
  • I made a change to the existing documentation and used the current branch.
• The documentation follows the Home Assistant documentation standards.

[j4n-e4t]

Great idea to expand the docs on the new Zigbee Groups feature. However, I would change the phrasing a bit 😉

[Hedda]

Great idea to expand the docs on the new Zigbee Groups feature. However, I would change the phrasing a bit

@j4n-e4t Thanks! I have commited your suggested changes now.

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[puddly]

Same as #28869

Let's keep this documentation specific to ZHA, so there's no need to explain what Zigbee groups are, how they're used, and so on. Just show/explain how to bind and unbind devices/groups.

[home-assistant]

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks 👍

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[Hedda]

Let's keep this documentation specific to ZHA, so there's no need to explain what Zigbee groups are, how they're used, and so on. Just show/explain how to bind and unbind devices/groups.

@puddly is this not better a start than not having any section about this? This is at least a beginning that others could build on.