fix: remove fractionalSecondDigits from es2020.intl.d.ts

fractionalSecondDigits is in ES2021 (unpublished), not ES2020

Author: longlho

src/lib/es2020.intl.d.ts

@@ -284,6 +284,5 @@ declare namespace Intl {
         dayPeriod?: "narrow" | "short" | "long";
         numberingSystem?: string;
         hourCycle?: "h11" | "h12" | "h23" | "h24";
-        fractionalSecondDigits?: 0 | 1 | 2 | 3;
     }
 }