feat: add filter_case_sensitive url parameter (#3910)

docs/en/parameter.md

@@ -36,6 +36,12 @@ Set `filterout` to exclude unwanted content.
 
 For example: [https://rsshub.app/dribbble/popular?filterout=Blue|Yellow|Black](https://rsshub.app/dribbble/popular?filterout=Blue|Yellow|Black)
 
+Set `filter_case_sensitive` to determine whether the filtering keywords should be case sensitive. The parameter would apply to both `filter` and `filterout`.
+
+Default: `true`
+
+Example: [https://rsshub.app/dribbble/popular?filter=BluE|yeLLow|BlaCK&filter_case_sensitive=false](https://rsshub.app/dribbble/popular?filter=BluE|yeLLow|BlaCK&filter_case_sensitive=false)
+
 ### Limit Entries
 
 Set `limit` to limit the number of articles in the feed.

docs/parameter.md

@@ -37,6 +37,12 @@ filterout 去掉不要的内容
 
 举例: <https://rsshub.app/bilibili/user/coin/2267573?filterout=微小微|赤九玖|暴走大事件>
 
+filter_case_sensitive 过滤是否区分大小写，filter 和 filterout 同时适用
+
+默认为 true，区分大小写
+
+举例 1: <https://rsshub.app/bilibili/user/coin/2267573?filter=diyGOD|RSShub&filter_case_sensitive=false>
+
 ## 条数限制
 
 可以使用 limit 参数限制最大条数, 主要用于排行榜类 RSS