docs: update week start docs

close #215 close #352

Author: iamkun

docs/en/API-reference.md

@@ -241,7 +241,7 @@ dayjs().subtract(7, "year");
 Returns a cloned `Dayjs` set to the start of the specified unit of time.
 
 ```js
-dayjs().startOf("week");
+dayjs().startOf("week"); // Depends on `weekStart` in locale
 ```
 
 ### End of Time `.endOf(unit: string)`

docs/es-es/API-reference.md

@@ -241,7 +241,7 @@ dayjs().subtract(7, "year");
 Devuelve un nuevo objeto `Dayjs`, resultante de ajustar el actual al principio de la unidad de tiempo indicada.
 
 ```js
-dayjs().startOf("week");
+dayjs().startOf("week"); // Depends on `weekStart` in locale
 ```
 
 ### Fin de `.endOf(unit: string)`

docs/ja/API-reference.md

@@ -278,7 +278,7 @@ Returns a new `Dayjs` object by by setting it to the start of a unit of time.
 
 ```js
 dayjs().startOf((unit: String));
-dayjs().startOf('year');
+dayjs().startOf('week'); // Depends on `weekStart` in locale
 ```
 
 #### End of Time

docs/ko/API-reference.md

@@ -238,7 +238,7 @@ dayjs().subtract(7, 'year');
 특정 시간 단위의 시작 시점에 대한 시간을 `Dayjs` 오브젝트 복제본으로 반환합니다.
 
 ```js
-dayjs().startOf('week');
+dayjs().startOf('week'); // Depends on `weekStart` in locale
 ```
 
 ### End of Time `.endOf(unit: string)`

docs/pt-br/API-reference.md

@@ -237,7 +237,7 @@ dayjs().subtract(7, 'year');
 Retorna um objeto `Dayjs` clonado definido com o começo da unidade de tempo especificada.
 
 ```js
-dayjs().startOf('week');
+dayjs().startOf('week'); // Depends on `weekStart` in locale
 ```
 
 ### Fim do Tempo `.endOf(unit: string)`

docs/zh-cn/API-reference.md

@@ -213,7 +213,7 @@ dayjs().subtract(7, 'year');
 返回当前时间的开头时间的 `Dayjs()` 对象，如月份的第一天。
 ```js
 dayjs().startOf(unit : String);
-dayjs().startOf('year');
+dayjs().startOf('week'); // 取决于 locale 文件里 `weekStart` 的值
 ```
 #### 末尾时间
 返回当前时间的末尾时间的 `Dayjs()` 对象，如月份的最后一天。