feat: add AWS::LanguageExtensions

[hoffa]

Issue #, if available:

Description of changes:

Adds AWS::LanguageExtensions by default, which resolves intrinsic functions known before deployment (see aws/serverless-application-model#2533).

Specifying it before the SAM transform, as described in this blog post.

Generated with:

grep -Frl -- '- AWS::Serverless-2016-10-31' | while IFS= read -r f; do sed -i.bak 's/- AWS::Serverless-2016-10-31/- AWS::LanguageExtensions\n- AWS::Serverless-2016-10-31/g' "$f"; done
grep -Frl 'Transform: AWS::Serverless-2016-10-31' | while IFS= read -r f; do sed -i.bak 's/Transform: AWS::Serverless-2016-10-31/Transform:\n- AWS::LanguageExtensions\n- AWS::Serverless-2016-10-31/g' "$f"; done
git clean -f

Tested with:

sam init --location aws-sam-cli-app-templates/python3.9/cookiecutter-aws-sam-hello-python

And deploying it.

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[aahung]

Is it possible to write a script to verify all generated template can pass sam validate?

[hoffa]

Closing for now; SAM CLI doesn't support AWS::LanguageExtensions.

[hoffa]

For posterity, some examples of weird behavior when together: aws-cloudformation/cfn-lint#1657 (comment) and aws/serverless-application-model#2778