Docs: add a couple of missing params/props

lib/input.js

@@ -430,6 +430,7 @@ function _isStreamInput () {
  * - `iptc`: Buffer containing raw IPTC data, if present
  * - `xmp`: Buffer containing raw XMP data, if present
  * - `tifftagPhotoshop`: Buffer containing raw TIFFTAG_PHOTOSHOP data, if present
+ * - `formatMagick`: String containing format for images loaded via *magick
  *
  * @example
  * const metadata = await sharp(input).metadata();