• add missing 'use Swagger.Streams;' clause
• add Style_Checks pragma to fix style compilation warnings in generated Ada code
• fix spurious spaces in licence headers that cause Ada style compilation warning
• update the default GNAT project config

Fix #8640

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
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  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh
  

  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
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