Swift: TSP message wording changes.

Co-authored-by: Isaac Brown <[email protected]>

Author: sashabu

swift/integration-tests/osx-only/autobuilder/only-tests/diagnostics.expected

@@ -2,7 +2,7 @@
   "helpLinks": [
     ""
   ],
-  "markdownMessage": "All targets found within Xcode projects or workspaces either have no Swift sources or are tests.\n\nTo analyze a custom set of source files, set up a [manual build command][1].\n\n[1]: https://docs.github.com/en/enterprise-server/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/configuring-the-codeql-workflow-for-compiled-languages#adding-build-steps-for-a-compiled-language",
+  "markdownMessage": "All targets found within Xcode projects or workspaces either contain no Swift source files, or are tests.\n\nTo analyze a custom set of source files, set up a [manual build command][1].\n\n[1]: https://docs.github.com/en/enterprise-server/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/configuring-the-codeql-workflow-for-compiled-languages#adding-build-steps-for-a-compiled-language",
   "severity": "error",
   "source": {
     "extractorName": "swift",