Add arm64 to example supported cpu values (#5756)

**What's the problem this PR addresses?**
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PR adds `arm64` to the list of example architectures for the CPU for the
`.yarnrc` config file. I added this given that it's probably one of the
most popular things people might add to this field given the existence
of the Apple M1/M2 machines, and that I originally stumbled onto this
field about just that, and the clickthrough to the node docs was
unnecessary if the docs just listed this field. There is precedent in
having the `arm64` field listed in the example per the `manifest.json`
file:


https://github.com/yarnpkg/berry/blob/2634e6ca9c1c63a17b9c2f679ae77f9d852ff5d2/packages/docusaurus/static/configuration/manifest.json#L69-L77

**How did you fix it?**
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By adding `arm64` to the list of supported CPU architectures.

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---------

Signed-off-by: Matthew Peveler <[email protected]>

packages/docusaurus/static/configuration/yarnrc.json

@@ -764,7 +764,7 @@
             "type": "string"
           },
           "default": [],
-          "_exampleItems": ["current", "x64", "ia32"]
+          "_exampleItems": ["current", "x64", "ia32", "arm64"]
         },
         "libc": {
           "title": "The list of standard C libraries to cover.",