Add explanation of how to change allowed inbound IP addresses

[craddm]

✅ Checklist

• You have given your pull request a meaningful title (e.g. Enable foobar integration rather than 515 foobar).
• You are targeting the develop branch.
• Your branch is up-to-date with the develop branch (you probably started your branch from develop but it may have changed since then).
• If-and-only-if your changes are not yet ready to merge, you have marked this pull request as a draft pull request and added '[WIP]' to the title.
• If-and-only-if you have changed any Powershell code, you have run the code formatter. You can do this with ./tests/AutoFormat_Powershell.ps1 -TargetPath <path to file or directory>.

⤴️ Summary

Adds some explanatory text to the Manage Users section. Question is, is this the right place for the instructions?

🌂 Related issues

Closes #1444

🔬 Tests

Built the documents locally.

[JimMadge]

@craddm Are you still working on this?

[craddm]

@JimMadge I was trying to think of whether there was a better place for the instructions, but I don't think there is, or that it's worth adding another section

[JimMadge]

Looks good.

I think it can fit in this section if we phrase it as "Enabling users to connect from approved locations" rather than "modifying network rules".

[edwardchalstrey1]

LGTM