Typing: ms with `StringValue` should not accept options

[meshuamam]

Currently, the definition of ms in the typing is:

declare function ms(value: StringValue, options?: Options): number;
declare function ms(value: number, options?: Options): string;

the StringValue version should not accept options, since it doesn't use it

[mrmckeb]

Great catch @meshuamam. Would you be interested in raising a PR with that change?