code: @Nonnull
    public ErrorTextProvider addItem (@Nonnull final EField eField, @Nonnull @Nonempty final String sText)
    {
      return addItem (new FormattableItem (eField, sText));
    }
docs: Add an error item to be disabled.
  
  @param eField
  The field to be used. May not be <code>null</code>.
  @param sText
  The text that should contain the placeholder ({@value #PLACEHOLDER})
  that will be replaced
  @return this for chaining