|targetGuid||The GUID of the target as returned by [[TargetGuidByName()]].|
|fileGuid||The GUID of the file.|
|tag||The name of the asset tag.|
Removes an asset tag for the given file.
This function does nothing if the file is not configured for building in the given target, or if the asset tag is not present in the list of asset tags configured for file. If the file was the last file referring to the given tag across the Xcode project, then the tag is removed from the list of known tags.