fix: update localeData plugin type (#1116)

Author: Mocha--

types/plugin/localeData.d.ts

@@ -4,7 +4,37 @@ declare const plugin: PluginFunc
 export = plugin
 
 declare module 'dayjs' {
+  type WeekdayNames = [string, string, string, string, string, string, string];
+  type MonthNames = [string, string, string, string, string, string, string, string, string, string, string, string];
+
+  interface InstanceLocaleDataReturn {
+    firstDayOfWeek(): number;
+    weekdays(instance?: Dayjs): WeekdayNames;
+    weekdaysShort(instance?: Dayjs): WeekdayNames;
+    weekdaysMin(instance?: Dayjs): WeekdayNames;
+    months(instance?: Dayjs): MonthNames;
+    monthsShort(instance?: Dayjs): MonthNames;
+    longDateFormat(format: string): string;
+  }
+
+  interface GlobalLocaleDataReturn {
+    firstDayOfWeek(): number;
+    weekdays(): WeekdayNames;
+    weekdaysShort(): WeekdayNames;
+    weekdaysMin(): WeekdayNames;
+    months(): MonthNames;
+    monthsShort(): MonthNames;
+    longDateFormat(format: string): string;
+  }
+
   interface Dayjs {
-    localeData(): any
+    localeData(): InstanceLocaleDataReturn;
   }
+
+  export function weekdays(localOrder?: boolean): WeekdayNames;
+  export function weekdaysShort(localOrder?: boolean): WeekdayNames;
+  export function weekdaysMin(localOrder?: boolean): WeekdayNames;
+  export function monthsShort(): MonthNames;
+  export function months(): MonthNames;
+  export function localeData(): GlobalLocaleDataReturn;
 }