Improve explanation of passive zones

[NoRi2909]

Proposed change

Currently the explanation for passive zones says that they "are not used as location for device trackers" which contradicts the second sentence that says: "This is useful if you just want to use it for automations.

So the first sentence says that they are not used while the second says they are just used for automations.

This PR clarifies that by changing the first sentence to "not shown as" and adds people beside device trackers because (active) zone names show up as the state of people, too.

In addition it fixes the plural / singular mismatch between the two sentences.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue or discussion:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

[NoRi2909]

We might want to use the word "state" instead of "location" in the first sentence. That a zone defines a location is inherently clear, so it does make sense to say exactly where they show up.