Describe the issue or suggestion

Some of the APIs in the System.Runtime.Intrinsics namespace are missing XML doc comments, even though they have <inheritdoc /> tags in the source code (example). We should populate the XML files in this folder with the appropriate inherited doc comments from the source code in the dotnet/runtime repo. Don't just insert <inheritdoc /> tags. Instead, to work around this issue, follow the inherit doc chain to find the actual documentation (for example, for Vector512.Max, follow the inheritdoc chain all the way up till ISimdVector<TSelf, T>.Max and copy the summary, parameter docs, returns, and exception docs from there).