Removed duplicate properties "list-style"

[glizer]

What do the changes you have made achieve?
Removed duplicate properties "list-style"

Are there any new warning messages?
No

Have you written tests?
No

Have you included relevant documentation
No

Which issues does this resolve?

<DCO 1.1 Signed-off-by: [email protected]>

[coveralls]

Coverage remained the same at 97.532% when pulling c90d2cb on glizer:removed-duplicate-prop into 52ccf2e on sasstools:develop.