move RegexpMetaChars into Regexp.qll

javascript/ql/src/semmle/javascript/Regexp.qll

@@ -1237,8 +1237,18 @@ module RegExp {
     }
   }
 
-  private class DefaultMetaCharacter extends MetaCharacter {
-    DefaultMetaCharacter() { this = ["<", "'", "\""] }
+  /**
+   * A meta character used by HTML.
+   */
+  private class HTMLMetaCharacter extends MetaCharacter {
+    HTMLMetaCharacter() { this = ["<", "'", "\""] }
+  }
+
+  /**
+   * A meta character used by regular expressions.
+   */
+  private class RegexpMetaChars extends RegExp::MetaCharacter {
+    RegexpMetaChars() { this = ["{", "[", "+"] }
   }
 
   /**

javascript/ql/src/semmle/javascript/security/dataflow/RegExpInjectionCustomizations.qll

@@ -71,11 +71,4 @@ module RegExpInjection {
       )
     }
   }
-
-  /**
-   * Meta characters used in the above sanitizer.
-   */
-  private class RegexpMetaChars extends RegExp::MetaCharacter {
-    RegexpMetaChars() { this = ["{", "[", "+"] }
-  }
 }