Add issue number to FIXMEs

Author: tmandry

compiler/rustc_target/src/spec/mod.rs

@@ -1109,10 +1109,10 @@ supported_targets! {
     ("x86_64-apple-darwin", x86_64_apple_darwin),
     ("i686-apple-darwin", i686_apple_darwin),
 
-    // FIXME(fuchsia): Remove aarch64-fuchsia in favor of aarch64-unknown-fuchsia
+    // FIXME(#106649): Remove aarch64-fuchsia in favor of aarch64-unknown-fuchsia
     ("aarch64-fuchsia", aarch64_fuchsia),
     ("aarch64-unknown-fuchsia", aarch64_unknown_fuchsia),
-    // FIXME(fuchsia): Remove x86_64-fuchsia in favor of x86_64-unknown-fuchsia
+    // FIXME(#106649): Remove x86_64-fuchsia in favor of x86_64-unknown-fuchsia
     ("x86_64-fuchsia", x86_64_fuchsia),
     ("x86_64-unknown-fuchsia", x86_64_unknown_fuchsia),