minify result, in, and in2 attributes

[bschlenk]

Is your feature request related to a problem? Please describe.
The result, in, and in2 attributes in a filter chain are always left as-is. However, as far as I can tell, these attributes are scoped to the particular <filter> element they are inside of. Would it make sense to minify these attributes?

Describe the solution you'd like
These attributes should be minified to single letter names where possible, making sure to match up in/in2 attributes with the corresponding result. Also make sure not to change the special values SourceGraphic | SourceAlpha | BackgroundImage | BackgroundAlpha | FillPaint | StrokePaint

Describe alternatives you've considered
Writing my own svgo plugin.

Additional context
Here's an example svg exported from Figma using <filter>, run through svgo, and theresult/in/in2 attributes remaining unminified:

<svg width="42" height="42" fill="none" viewBox="0 0 42 42">
  <g filter="url(#id-a)">
    <path
      fill="white"
      d="M9 18c0-6.627 5.373-12 12-12s12 5.373 12 12-5.373 12-12 12H11a2 2 0 0 1-2-2z"
    />
    <path
      stroke="white"
      d="M21 5.5c6.904 0 12.5 5.596 12.5 12.5S27.904 30.5 21 30.5H11A2.5 2.5 0 0 1 8.5 28V18c0-6.904 5.596-12.5 12.5-12.5Z"
    />
  </g>
  <path
    fill="black"
    d="M21 28v2H11v-2zm10-10c0-5.523-4.477-10-10-10s-10 4.477-10 10v12l-.204-.01a2 2 0 0 1-1.785-1.786L9 28V18c0-6.627 5.373-12 12-12s12 5.373 12 12-5.373 12-12 12v-2c5.523 0 10-4.477 10-10"
  />
  <defs>
    <filter
      id="id-a"
      width="42"
      height="42"
      x="0"
      y="0"
      color-interpolation-filters="sRGB"
      filterUnits="userSpaceOnUse"
    >
      <feFlood flood-opacity="0" result="BackgroundImageFix" />
      <feColorMatrix
        in="SourceAlpha"
        result="hardAlpha"
        values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 127 0"
      />
      <feOffset dy="1" />
      <feGaussianBlur stdDeviation="1.5" />
      <feColorMatrix values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.1 0" />
      <feBlend in2="BackgroundImageFix" result="effect1_dropShadow_9843_4233" />
      <feColorMatrix
        in="SourceAlpha"
        result="hardAlpha"
        values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 127 0"
      />
      <feOffset dy="3" />
      <feGaussianBlur stdDeviation="4" />
      <feColorMatrix values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.1 0" />
      <feBlend
        in2="effect1_dropShadow_9843_4233"
        result="effect2_dropShadow_9843_4233"
      />
      <feColorMatrix
        in="SourceAlpha"
        result="hardAlpha"
        values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 127 0"
      />
      <feOffset />
      <feGaussianBlur stdDeviation=".25" />
      <feColorMatrix values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.18 0" />
      <feBlend
        in2="effect2_dropShadow_9843_4233"
        result="effect3_dropShadow_9843_4233"
      />
      <feBlend
        in="SourceGraphic"
        in2="effect3_dropShadow_9843_4233"
        result="shape"
      />
    </filter>
  </defs>
</svg>