Umlauts in Requirement IDs are not allowed.

[sebastianohl]

Description

If a requirement ID contain an Umlaut (e.g. ö ä ü), it is ignored for tracing. This is in contradiction to the User Guide (https://github.com/itsallcode/openfasttrace/blob/main/doc/user_guide.md#specification-item-id). The definition is that the ID can contain any ASCII character ("The name part of the ID must be a character string consisting of ASCII letters and or numbers separated by underscore ("_"), hyphen ("-") or dot ("."). Whitespaces are not allowed.").

Steps to Reproduce

1. Create this requirement and store it to a md file:
   ### Die Implementierung muss den Zustand einzelner Zellen ändern. reqzellzustandsänderung1`
   Status: proposed

Description:
Diese Anforderung ermöglicht die Aktualisierung des Zustands von lebenden und toten Zellen in jeder Generation.

Needs: arch`
3. run java -jar openfasttrace-3.7.0.jar trace *.md

Expected behavior

The expectation is that the trace complains about the not covered requirement rather than ignoring it.

Environment

• OFT: 3.7.0
• OS: Ubuntu 22.04
• Java Version: openjdk version "19.0.2" 2023-01-17