[css] missing colon causes error to be placed on next rule

Testing: https://github.com/microsoft/vscode/issues/172045 It seems to highlight the incorrect section but it does have the correct error message. It makes it more confusing but isn't necessarily broken in that it still correctly identifies the error. <img width="611" alt="Screenshot 2023-01-24 at 9 02 10 AM" src="https://user-images.githubusercontent.com/26030610/214373430-3a6e697f-6d60-479f-88f4-4d2dfac0d82f.png">