code: @Nonnull
      public final Word<I> subWord(int fromIndex) {
          if (fromIndex <= 0) {
              if (fromIndex == 0) {
                  return this;
              }
              throw new IndexOutOfBoundsException("Invalid subword range [" + fromIndex + ",)");
          }
          return subWordInternal(fromIndex, length());
      }
docs: Retrieves the subword of this word starting at the given index and extending until the end of this word. Calling
  this method is equivalent to calling
  <pre>w.subWord(fromIndex, w.length())</pre>
  
  @param fromIndex
  the first index, inclusive
  
  @return the word representing the specified subrange