Implement CSS Text Module Level 3

for example:
```shell
python -m cssutils.scripts.cssparse -s 'a {word-break: normal;}'
WARNING Property: Unknown Property name. [1:4: word-break]
b'a {\n word-break: normal\n }'
```

Can I help? Where to start?

Start with the cssutils.scripts.cssparse entry point and the CSS Text Module Level 3 specification, using the reported word-break warning as the concrete example. Determine which module features and properties are in scope, then define tests that demonstrate the supported syntax is parsed without the warning; completion depends on an agreed implementation scope.

Written by the indexing model from the issue text.