This PR updates the webidl files for `TextEncoder` and `TextDecoder`.
For `TextDecoder.webidl`, the type `AllowSharedBufferSource`, as defined
in the latest spec, is replaced with `BufferSource` as servo currently
does not support `ShareArrayBuffer`
Testing: This update does not introduce any change to the generated rust
binding, so the existing testing would suffice
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Signed-off-by: Minghua Wu <michael.wu1107@gmail.com>
Signed-off-by: Xiaocheng Hu <xiaochengh.work@gmail.com>
Co-authored-by: Xiaocheng Hu <xiaochengh.work@gmail.com>
