Use platform independent line break in test

src/test/java/com/keenwrite/processors/markdown/ImageLinkExtensionTest.java

		private static String toHtml( final String url ) {
		return format(
		- "<p><img src=\"%s\" alt=\"Tooltip\" title=\"Title\" /></p>\n", url );
		+ "<p><img src=\"%s\" alt=\"Tooltip\" title=\"Title\" /></p>%n", url );
		}

Delta	1 line added, 1 line removed