Update documentation for Windows ClassPath for Managed service type

[pauby]

Describe the bug
I spent quite a bit of time troubleshooting this and discovered that the paths to be used on Windows are not the 'native filesystem separator' as specified in the Managed: Class Path help, but are Unix / Linux path separators.

The Chocolatey package that I maintain installs LanguageTool into c:\tools\languagetool.

This works:

This doesn't:

(Note the path separators)

To Reproduce
Hopefully the above gives enough information. If not, let me know.

Expected behavior
The help text for the Managed: Class Path entry in the Settings specifies that Unix / Linux style path separators are used.

Screenshots
Hopefully that's not needed.

Environment & Configuration (please complete the following information):

• OS + Version: Windows 10
• VS Code Version: 1.78.2 (2 weeks old).
• LanguageTool Linter Version: 0.20.0
• LanguageTool Version: 6.1
• Service Configuration: managed
• Service Classpath (if 'managed'): c:\tools\languagetool*.jar

Additional context
I appreciate that in the Wiki you don't provide any help for Windows. Hopefully this adds something.