Add missing visionOS target metadata

Author: agg23

compiler/rustc_target/src/spec/targets/aarch64_apple_visionos.rs

@@ -8,7 +8,12 @@ pub fn target() -> Target {
 
     Target {
         llvm_target: visionos_llvm_target(arch).into(),
-        description: None,
+        metadata: crate::spec::TargetMetadata {
+            description: None,
+            tier: None,
+            host_tools: None,
+            std: None,
+        },
         pointer_width: 64,
         data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".into(),
         arch: arch.target_arch(),

compiler/rustc_target/src/spec/targets/aarch64_apple_visionos_sim.rs

@@ -8,7 +8,12 @@ pub fn target() -> Target {
 
     Target {
         llvm_target: visionos_sim_llvm_target(arch).into(),
-        description: None,
+        metadata: crate::spec::TargetMetadata {
+            description: None,
+            tier: None,
+            host_tools: None,
+            std: None,
+        },
         pointer_width: 64,
         data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".into(),
         arch: arch.target_arch(),