Handle SVG as its own language

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I just tried to disable auto-formatting for SVG like this:

  "[svg]": {
    "editor.formatOnSave": false
  }

However, [svg] is not a valid language and therefore it doesn't work.
Instead you have to use [xml], which I don't want to use since I still want it to auto-format any "real" XML files.

IMHO: SVG is branched off from XML (just like HTML) and warrants its own language specifier.