docs: update javadoc

- Update package path for o.l.l.en.English class

Signed-off-by: Hiroshi Miura <miurahr@linux.com>

languagetool-core/src/main/java/org/languagetool/Languages.java

@@ -158,7 +158,7 @@ static boolean hasPremium(String className) {
   /**
    * Get the Language object for the given language class name or try to create it and add to dynamic languages.
    *
-   * @param className e.g. <code>org.languagetool.language.English</code>
+   * @param className e.g. <code>org.languagetool.language.en.English</code>
    * @return a Language object
    * @throws RuntimeException if language not found in classpath
    * @since 5.0