[clang-tools-extra] [clang-doc] refactor JSONGenerator array usage (PR #145595)

[Erick Velez via cfe-commits]

evelez7 wrote:

### Merge activity

* **Jun 26, 5:09 PM UTC**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/145595).


https://github.com/llvm/llvm-project/pull/145595