add aarch64-apple-ios-sim to platform-support.md

Author: Ricky (deg4uss3r)

src/doc/rustc/src/platform-support.md

@@ -153,6 +153,7 @@ not available.
 target | std | host | notes
 -------|-----|------|-------
 `aarch64-apple-ios-macabi` | ? |  | Apple Catalyst on ARM64
+`aarch64-apple-ios-sim` | ? |  | Apple iOS Simulator on  ARM64
 `aarch64-apple-tvos` | * |  | ARM64 tvOS
 `aarch64-unknown-freebsd` | ✓ | ✓ | ARM64 FreeBSD
 `aarch64-unknown-hermit` | ? |  |