Fix parsing and writing of CSS HSL and HWB values where 's', 'l', 'w', and 'b' range from 0.0 to 100.0.

Previous code assumed 's','l', 'w', and 'b' had ranges of 0.0 to 1.0.

See

• https://www.w3.org/TR/css-color-4/#the-hsl-notation
• https://www.w3.org/TR/css-color-4/#the-hwb-notation

Fixes #5935 (closed)