Remove TODO

Author: MattiasBuelens

index.bs

@@ -9363,7 +9363,6 @@ a reference to the same object that the IDL value represents.
             {{ArrayBuffer/byteLength|ArrayBuffer.prototype.byteLength}} or
             {{SharedArrayBuffer/byteLength|SharedArrayBuffer.prototype.byteLength}}.
 </div>
-<!-- TODO: should this be stricter around not being detached? -->
 
 <div algorithm>
     An {{ArrayBufferView}} instance |view| is