docs(script-sdk): add docs for headers - INS-5438

[ihexxa]

Changes

• docs(script-sdk): add docs for headers

[Copilot]

Pull Request Overview

This PR enhances the documentation for HTTP header handling in the scripting SDK while aligning tests with the updated header interface.

• Removed the deprecated “type” property from header definitions and updated tests accordingly.
• Added comprehensive JSDoc comments to the Header and HeaderList classes to improve clarity and usage.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
packages/insomnia-smoke-test/tests/smoke/pre-request-script-features.test.ts	Removed the unused "type" property from the header object in tests.
packages/insomnia-scripting-environment/src/objects/headers.ts	Enhanced the documentation for headers, removed the "type" property in the HeaderDefinition, and updated related constructor logic.

Comments suppressed due to low confidence (1)

packages/insomnia-scripting-environment/src/objects/headers.ts:169

• The declared type for headerArray is inconsistent since unparseSingle returns a string. Consider changing the type to string[] and removing the unnecessary spread operator to avoid potential runtime issues.

const headerArray: { key: string; value: string }[] = [...headers.map(header => this.unparseSingle(header), {})];