Escape path for the local Javadoc

[PwtKCL]

This ticket is created based on a support email received on 22/03/2024.

From BlueJ 5.3.0, a local path for the JavaDoc can no longer be set via the interface.
However, it is still possible to read the path from BlueJ defs / properties files.

The current implementation requires the path in those files to contain escaped characters so that Java can read them properly.

We should probably let the users write the path as it is, and escape ourselves when retrieving the string in the file.
An example is having "µ" inside the path of the local JavaDoc.

Regardless we let the users inserting the path "as is" or not, in all cases we should update the BlueJ FAQ regarding setting the local JavaDoc as it is anyway outdated.