Some string identifiers result in Unable to generate an IRI error

[NotionCommotion]

When using a scalar string as the identifier, an Unable to generate an IRI error occurs based on the content of the string. This occurs if a forward slash (/) is in the string and has been identified already by issue 2953. It also occurs if there is a period (.) in the string. Please add a list of characters which cannot be in the string to the scalar string documentation, and also potentially the solution described by dardinier.