Add space to make error message readable.
Was: "MyClassis not in the transitive Java deps of included j2objc_library rules"

RELNOTES: None.
PiperOrigin-RevId: 164466271
diff --git a/tools/objc/j2objc_dead_code_pruner.py b/tools/objc/j2objc_dead_code_pruner.py
index a5693fb..3377fc9 100755
--- a/tools/objc/j2objc_dead_code_pruner.py
+++ b/tools/objc/j2objc_dead_code_pruner.py
@@ -106,7 +106,7 @@
   for entry_class in entry_classes.split(','):
     if entry_class not in header_mapping:
       raise Exception(entry_class +
-                      'is not in the transitive Java deps of included ' +
+                      ' is not in the transitive Java deps of included ' +
                       'j2objc_library rules.')
     transpiled_entry_files.append(header_mapping[entry_class])