doc: add arm64 to os.machine()

PR-URL: #45374
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/os.md

@@ -460,8 +460,8 @@ added: v18.9.0
 
 * Returns {string}
 
-Returns the machine type as a string, such as `arm`, `aarch64`, `mips`,
-`mips64`, `ppc64`, `ppc64le`, `s390`, `s390x`, `i386`, `i686`, `x86_64`.
+Returns the machine type as a string, such as `arm`, `arm64`, `aarch64`,
+`mips`, `mips64`, `ppc64`, `ppc64le`, `s390`, `s390x`, `i386`, `i686`, `x86_64`.
 
 On POSIX systems, the machine type is determined by calling
 [`uname(3)`][]. On Windows, `RtlGetVersion()` is used, and if it is not