Anki maturity-based known-word highlighting (#172)

src/types/runtime-options.ts

@@ -1,6 +1,7 @@
 export type RuntimeOptionId =
   | 'anki.autoUpdateNewCards'
   | 'subtitle.annotation.knownWords.highlightEnabled'
+  | 'subtitle.annotation.knownWords.maturityEnabled'
   | 'subtitle.annotation.nPlusOne'
   | 'subtitle.annotation.jlpt'
   | 'subtitle.annotation.frequency'