fix: refuse a mistyped --target in cross_reference

load_target_config raised out of cross_reference.py as a traceback. The hint now names the full verify.py command, since cross_reference and slots have no --list-targets.

scripts/common.py

@@ -658,8 +658,11 @@ def load_target_config(
         # through, where a platform or emulator name gets the closest ones.
         raise ValueError(
             f"Unknown target '{target}' for platform '{platform_name}'.\n"
+            # Named as a full command: cross_reference.py and slots.py take
+            # --target but have no --list-targets of their own.
             + suggest_names(
-                [target], sorted(alias_index), "--list-targets", len(targets)
+                [target], sorted(alias_index),
+                f"verify.py --platform {platform_name} --list-targets", len(targets),
             )
         )
 

scripts/cross_reference.py

@@ -979,11 +979,16 @@ def main() -> None:
     if args.platform:
         from common import load_target_config, resolve_platform_cores
 
-        target_cores = (
-            load_target_config(args.platform, args.target, args.platforms_dir)
-            if args.target
-            else None
-        )
+        try:
+            target_cores = (
+                load_target_config(args.platform, args.target, args.platforms_dir)
+                if args.target
+                else None
+            )
+        except (FileNotFoundError, ValueError) as exc:
+            # A typo ended in a traceback where verify and slots name the
+            # closest target.
+            parser.error(str(exc))
         config = load_platform_config(args.platform, args.platforms_dir)
         relevant = resolve_platform_cores(config, profiles, target_cores=target_cores)
         run_anywhere = (