Add comment to workaround Python2 SyntaxError

Commented out code is the proper scenario but cannot be used as the test
file is run under Python2

rollbar/test/test_rollbar.py

@@ -396,6 +396,8 @@ def test_get_request_fastapi_middleware(self):
         # Inject annotations and decorate endpoint dynamically
         # to avoid SyntaxError for older Python
         #
+        # This is the code we'd use if we had not loaded the test file on Python 2.
+        #
         # @app.get('/{param}')
         # def root(param, fastapi_request: Request):
         #     current_request = rollbar.get_request()
@@ -431,6 +433,8 @@ def test_get_request_fastapi_logger(self):
         # Inject annotations and decorate endpoint dynamically
         # to avoid SyntaxError for older Python
         #
+        # This is the code we'd use if we had not loaded the test file on Python 2.
+        #
         # @app.get('/{param}')
         # def root(fastapi_request: Request):
         #     current_request = rollbar.get_request()
@@ -470,6 +474,8 @@ def test_get_request_fastapi_router(self):
         # Inject annotations and decorate endpoint dynamically
         # to avoid SyntaxError for older Python
         #
+        # This is the code we'd use if we had not loaded the test file on Python 2.
+        #
         # @app.get('/{param}')
         # def root(fastapi_request: Request):
         #     current_request = rollbar.get_request()