feat: contributes.yamlValidation

[Malix-Labs]

I do no know if there would be another better URL than from https://json.schemastore.org/, feel free to suggest

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds built-in YAML schema validation for GitHub issue template files by registering yamlValidation contributions in the extension manifest.

Changes:

• Registers schema validation for GitHub issue form templates under .github/ISSUE_TEMPLATE/ (excluding config.{yml,yaml}).
• Registers schema validation for the issue template config.{yml,yaml} file.

[alexr00]

Cool, thank you!

[alexr00]

/AzurePipelines run

[azure-pipelines]

Azure Pipelines could not run because the pipeline triggers exclude this branch/path.

[Malix-Labs]

yw @alexr00 <3

also please read #8761 (comment)

+ I strongly recommend you test it in your end to see if it works by default without needing any more extensions, since my setup is highly customized and have many extensions and non-default settings

there might be a better URL I'm not (or even cannot be) aware of

[alexr00]

Looks like we already allow schemastore.org:

https://github.com/microsoft/vscode/blob/25afc315fe0f791309594255cc27a73b43a2ae95/extensions/json-language-features/package.json#L137

[Malix-Labs]

@alexr00 yes indeed, but since Microsoft owns both GitHub Issues and thus its schema, isn't there a a static file in this repository / another Microsoft repository which could provide this yml schema as a path instead of relying on that external CDN?