Qt Linguist: Improve support for soft hyphens

Background

• https://en.wikipedia.org/wiki/Soft_hyphen
• https://unicode-explorer.com/c/00AD

Examining the current behaviour

1. Build and run the attached project
2. Resize the QLabel – Notice the appearance and disappearance of soft hyphens
3. Inspect HelloLinguist_ms_MY.ts – Notice the presence of handcrafted "&#173 ;" entities to encode the soft hyphens
4. Open HelloLinguist_ms_MY.ts in Qt Linguist – Notice that the soft hyphens have been decoded and are now invisible
5. Save the file in Qt Linguist (or run lupdate on the project) – Notice that "&#173 ;" has now been replaced by the literal bytes "0xC2AD"

Requirements

The customer would like a way to visualize and enter soft hyphens in Qt Linguist directly.

If this is not feasible, at least save the soft hyphen in escaped form ("&#173 ;" or "&xad ;") in the .ts file to support manual editing and source code control.