Force the environment variable to be non-empty?

Author: grynspan

.github/workflows/pull_request.yml

@@ -17,13 +17,14 @@ jobs:
       linux_os_versions: '["amazonlinux2", "jammy"]'
       windows_swift_versions: '["nightly-main", "nightly-6.2"]'
       enable_macos_checks: true
-      macos_exclude_xcode_versions: "[{\"xcode_version\": \"16.2\"}, {\"xcode_version\": \"16.3\"}]"
+      macos_exclude_xcode_versions: "[{\"xcode_version\": \"16.2\"}, {\"xcode_version\": \"16.3\"}, {\"xcode_version\": \"16.4\"}]"
       enable_wasm_sdk_build: true
   soundness:
     name: Soundness
     uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
     with:
       license_header_check_project_name: "Swift"
       docs_check_container_image: "swift:6.2-noble"
+      docs_check_additional_arguments: "--emit-digest"
       format_check_enabled: false
       api_breakage_check_enabled: false