Anchors for Glossary Items starting with a Digit

When rendering a link from a short or abbreviated form of a glossary item to the long form, the link does not work in case the term starts with a digit.

The issue is based on the HTML specification which does not allow identifiers to start with a digit. If this is the case and we construct our IDs for the glossary, we need to check if the raw name starts with a digit and adjust the generated ID accordingly.