code: public static String appendIfMissingIgnoreCase(final String str, final CharSequence suffix, final CharSequence... suffixes) {
          return appendIfMissing(str, suffix, true, suffixes);
      }
docs: Appends the suffix to the end of the string if the string does not
  already end, case insensitive, with any of the suffixes.
  
  <pre>
  StringUtils.appendIfMissingIgnoreCase(null, null) = null
  StringUtils.appendIfMissingIgnoreCase("abc", null) = "abc"
  StringUtils.appendIfMissingIgnoreCase("", "xyz") = "xyz"
  StringUtils.appendIfMissingIgnoreCase("abc", "xyz") = "abcxyz"
  StringUtils.appendIfMissingIgnoreCase("abcxyz", "xyz") = "abcxyz"
  StringUtils.appendIfMissingIgnoreCase("abcXYZ", "xyz") = "abcXYZ"
  </pre>
  <p>With additional suffixes,</p>
  <pre>
  StringUtils.appendIfMissingIgnoreCase(null, null, null) = null
  StringUtils.appendIfMissingIgnoreCase("abc", null, null) = "abc"
  StringUtils.appendIfMissingIgnoreCase("", "xyz", null) = "xyz"
  StringUtils.appendIfMissingIgnoreCase("abc", "xyz", new CharSequence[]{null}) = "abcxyz"
  StringUtils.appendIfMissingIgnoreCase("abc", "xyz", "") = "abc"
  StringUtils.appendIfMissingIgnoreCase("abc", "xyz", "mno") = "axyz"
  StringUtils.appendIfMissingIgnoreCase("abcxyz", "xyz", "mno") = "abcxyz"
  StringUtils.appendIfMissingIgnoreCase("abcmno", "xyz", "mno") = "abcmno"
  StringUtils.appendIfMissingIgnoreCase("abcXYZ", "xyz", "mno") = "abcXYZ"
  StringUtils.appendIfMissingIgnoreCase("abcMNO", "xyz", "mno") = "abcMNO"
  </pre>
  
  @param str The string.
  @param suffix The suffix to append to the end of the string.
  @param suffixes Additional suffixes that are valid terminators.
  
  @return A new String if suffix was appended, the same string otherwise.
  
  @since 3.2