Support jest-environment directive

[CalebAlbers]

🛠️ Description

From an internal report:

---

Our JS testing library, jest, has a feature to specify a test environment per-file using a comment at the top, like this:

/**
 * @jest-environment jsdom
 */

Per the docs, the heuristic here is:

Any docblock pragmas in test files will be passed to the environment constructor and can be used for per-test configuration.

What's happening is that when the copyright header is added to the top of the file, it takes the place of the existing docblock and the jest-environment specification isn't respected:

/**
 * Copyright (c) HashiCorp, Inc.
 * SPDX-License-Identifier: MPL-2.0
 */

/**
 * @jest-environment jsdom
 */

---

Given that the @jest-environment directive needs to be in the first docblock, this PR adds support for inline docblocks specifically using the @jest-environment directive.

🔗 External Links

https://hashicorp.atlassian.net/browse/ENGSYS2-601

👍 Definition of Done

• New functionality works?
• Tests added?

🤔 Can be merged upon approval?

✅

[BRKalow]

💯

[dlaguerta]

🚀 thank you!