Add format_pie_symbol function

What does this MR do?

This MR adds format_pie_symbol to ABC.Interpreter, which returns a human readable string representing the symbol that is located at a given program location. We already use this function within Internal.WebService but would also like to use it in VIIA.

To avoid duplication we figured this would be the most appropriate location for such a function.

This MR is related to https://gitlab.com/top-software/viia/-/merge_requests/657.

Changes to public APIs

Author's checklist (required)

• If bugs have been solved, tests have been added (guidelines)
• A changelog entry has been added (guidelines)
• Newly added code is documented (guidelines)
• Newly added code has a style consistent with the rest of the repository
• Intermediate commits compile (use git rebase -i main if not)

Related issues