[Copilot Dreaming] Reduce upkeep by removing duplicate build descriptions

Maintainers have two copies of the compilation and tracked-output
descriptions to update when the build layout changes. The same Copilot
reader already receives both descriptions in the overview, so removing
the repeated narration avoids that extra upkeep.
3ea37a44b6/.github/copilot-instructions.md (L8-L10)

No prohibition, check, or limit is removed. Generated-code review
exclusions and freshness-check guidance still apply in Generated code.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/copilot-instructions.md

@@ -21,7 +21,7 @@ The CodeQL Action is used in GitHub Actions workflows to run CodeQL scans using
 
 ## Generated code
 
-The main codebase of the CodeQL Action is written in TypeScript and compiled to JavaScript. Both the TypeScript sources and the **generated** JavaScript code are contained in this repository. The TypeScript sources are contained in the `src` directory and the JavaScript code is contained in the `lib` directory. A GitHub Actions workflow checks that the JavaScript code in `lib` is up-to-date. Therefore, you should not review any changes to the contents of the `lib` folder and it is expected that the JavaScript code in `lib` closely mirrors the TypeScript code it is generated from. The secondary TypeScript codebase has sources in the `pr-checks` directory, which are executed directly with `tsx` and not compiled to JavaScript in the `lib` folder.
+The TypeScript sources are contained in the `src` directory and the JavaScript code is contained in the `lib` directory. A GitHub Actions workflow checks that the JavaScript code in `lib` is up-to-date. Therefore, you should not review any changes to the contents of the `lib` folder and it is expected that the JavaScript code in `lib` closely mirrors the TypeScript code it is generated from. The secondary TypeScript codebase has sources in the `pr-checks` directory, which are executed directly with `tsx` and not compiled to JavaScript in the `lib` folder.
 
 GitHub Actions workflows in the `.github/workflows` directory whose filenames start with two underscores (e.g. `__all-platform-bundle.yml`) are automatically generated using the `pr-checks/sync.sh` script from template files in the `pr-checks/checks` directory. Therefore, you do not need to review files in the `.github/workflows` directory that start with two underscores. However, you should review changes to the `pr-checks` directory as well as workflows in the `.github/workflows` directory that do not start with underscores.