[Experiment codegen tool] Fix a missing namespace comment in Python experiment compiler: tools/codegen/core/experiments_compiler.py.

PiperOrigin-RevId: 766263446

Author: nanahpang

tools/codegen/core/experiments_compiler.py

@@ -529,7 +529,7 @@ def _GenerateExperimentsSrcForPlatform(self, platform, mode, file_desc):
             if "kDefaultForDebugOnly" in have_defaults:
                 print("const bool kDefaultForDebugOnly = true;", file=file_desc)
             print("#endif", file=file_desc)
-        print("}", file=file_desc)
+        print("}  // namespace", file=file_desc)
         print(file=file_desc)
         print("namespace grpc_core {", file=file_desc)
         print(file=file_desc)