Fix incorrect regex patterns in README files (realm#3393)

README.md

@@ -398,15 +398,15 @@ custom_rules:
     included: ".*\\.swift" # regex that defines paths to include during linting. optional.
     excluded: ".*Test\\.swift" # regex that defines paths to exclude during linting. optional
     name: "Pirates Beat Ninjas" # rule name. optional.
-    regex: "([n,N]inja)" # matching pattern
+    regex: "([nN]inja)" # matching pattern
     capture_group: 0 # number of regex capture group to highlight the rule violation at. optional.
     match_kinds: # SyntaxKinds to match. optional.
       - comment
       - identifier
     message: "Pirates are better than ninjas." # violation message. optional.
     severity: error # violation severity. optional.
   no_hiding_in_strings:
-    regex: "([n,N]inja)"
+    regex: "([nN]inja)"
     match_kinds: string
 ```
 

README_CN.md

@@ -294,14 +294,14 @@ reporter: "xcode" # 报告类型 (xcode, json, csv, checkstyle, junit, html, emo
 custom_rules:
   pirates_beat_ninjas: # 规则标识符
     name: "Pirates Beat Ninjas" # 规则名称，可选
-    regex: "([n,N]inja)" # 匹配的模式
+    regex: "([nN]inja)" # 匹配的模式
     match_kinds: # 需要匹配的语法类型，可选
       - comment
       - identifier
     message: "Pirates are better than ninjas." # 提示信息，可选
     severity: error # 提示的级别，可选
   no_hiding_in_strings:
-    regex: "([n,N]inja)"
+    regex: "([nN]inja)"
     match_kinds: string
 ```
 

README_KR.md

@@ -270,14 +270,14 @@ custom_rules:
   pirates_beat_ninjas: # 룰 식별자
     included: ".*.swift" # 린트 실행시 포함할 경로를 정의하는 정규표현식. 선택 가능.
     name: "Pirates Beat Ninjas" # 룰 이름. 선택 가능.
-    regex: "([n,N]inja)" # 패턴 매칭
+    regex: "([nN]inja)" # 패턴 매칭
     match_kinds: # 매칭할 SyntaxKinds. 선택 가능.
       - comment
       - identifier
     message: "Pirates are better than ninjas." # 위반 메시지. 선택 가능.
     severity: error # 위반 수준. 선택 가능.
   no_hiding_in_strings:
-    regex: "([n,N]inja)"
+    regex: "([nN]inja)"
     match_kinds: string
 ```