Documentation Update: Describe the use of %COMPUTERNAME%\Name for local user and group

[PeetMcK]

Unless I'm missing something GitHub doesn't seem to allow pull requests on wiki repos.

On the Registry Settings](https://github.com/pseymour/MakeMeAdmin/wiki/Registry-Settings) page in the wiki, please consider adding the following: "Names of local users or groups should be in the format %COMPUTERNAME%\Name"

The final text for footnote ² would be as follows:

² : Names of users or groups should be in the format DOMAIN\Name. User principal names (e.g., [email protected]) will not work. Names of local users or groups should be in the format %COMPUTERNAME%\Name.