Fix build warning #128

Job	Run time
Validate generated code	2m 54s
Run tests using swift-syntax-dev-utils (Linux)	24m 40s
Run tests using swift-syntax-dev-utils (Windows)	48m 2s
Test / Windows (5.9 - windows-2022)	19m 53s
Test / Linux (5.9 - jammy)	3m 53s
Test / Windows (6.0 - windows-2022)	21m 50s
Test / Linux (5.10 - jammy)	3m 50s
Test / Windows (nightly - windows-2019)	15m 49s
Test / Linux (6.0 - jammy)	4m 14s
Test / Windows (nightly-6.1 - windows-2019)	15m 32s
Test / Linux (nightly-main - jammy)	4m 56s
Test / Linux (nightly-6.1 - jammy)	4m 49s
Soundness / API breakage check	0s
Soundness / Documentation check	4m 48s
Soundness / Unacceptable language check	4s
Soundness / Broken symlinks check	5s
Soundness / Format check	44s
Soundness / License headers check	10s
Soundness / Python lint check	4s
Soundness / Shell check	36s
Soundness / YAML lint check	3s
	2h 56m 56s

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