Tweak comparison formatting

tests/test_reference_runs/test_pre_deployment.py

@@ -266,14 +266,15 @@ class ComparisonResult:
     def show(self):
         if not self.found_differences():
             print(f"{self.filename} - ✓ no changes")
+            return
 
         print(self.filename)
         for ds in self.new_dsets:
-            print(f"  + NEW {ds}")
+            print(f"  + NEW: {ds}")
         for ds in self.missing_dsets:
-            print(f"  - DEL {ds}")
+            print(f"  - MISSING: {ds}")
         for ds in self.changed_dsets:
-            print(f"  ~ DIF {ds}")
+            print(f"  ~ CHANGED: {ds}")
 
 def gather_dsets(f: h5py.File):
     res = set()