code: private String escapeForFuzzy(String word) {
          int length = word.length();
          char[] tmp = new char[length * 4];
          length = ASCIIFoldingFilter.foldToASCII(word.toCharArray(), 0, tmp, 0, length);
          return new String(tmp, 0, length);
      }
docs: Apply same filtering as "custom" analyzer. Lowercase is done by QueryParser for fuzzy search.
  
  @param word word
  @return word escaped