Documentation: CSS setting is incorrect.

[RobbyCBennett]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.86.2 (system setup)
• OS Version: Windows 11 (Windows_NT x64 10.0.22631)

Steps to Reproduce:

1. Enable the built-in extension "CSS Language Features", which has an identifier of vscode.css-language-features
2. In settings, search for "hex color length"

See that it says "Hex colors must consist of three or six hex numbers." when it should say "Hex colors must consist of three, four, six, or eight hex numbers." to accommodate the alpha channel.

The extension already allows for all four lengths, but the setting description is wrong.