fix(build): use @buschtoens/documentation

Fixes emberjs#596.

Includes a fix for building from `.ts` source files.

documentationjs/documentation#1484

package.json

@@ -27,7 +27,7 @@
     "prepack": "yarn build && run-s build:*:verify",
     "postpack": "yarn clean",
     "build": "run-p --aggregate-output build:*",
-    "build:docs": "documentation build --document-exported \"addon-test-support/@ember/test-helpers/index.js\" --config documentation.yml --markdown-toc-max-depth 3 -f md -o API.md",
+    "build:docs": "documentation build --pe .ts --pe .d.ts --document-exported \"addon-test-support/@ember/test-helpers/index.ts\" --config documentation.yml --markdown-toc-max-depth 3 -f md -o API.md",
     "build:docs:verify": "git diff --quiet API.md || (echo '`API.md` has changed, please run `yarn build:docs` & commit the changes to update the API documentation' && exit 1)",
     "build:js": "yarn babel --extensions '.ts' --presets @babel/preset-typescript addon-test-support --out-dir addon-test-support/ --ignore '**/*.d.ts'",
     "clean": "run-p --aggregate-output clean:*",
@@ -61,7 +61,7 @@
     "@typescript-eslint/parser": "^4.29.0",
     "broccoli-babel-preset-typescript": "^1.0.1",
     "broccoli-merge-trees": "^4.2.0",
-    "documentation": "^13.2.5",
+    "documentation": "npm:@buschtoens/documentation@13.2.6",
     "ember-auto-import": "^2.2.0",
     "ember-cli": "~3.28.3",
     "ember-cli-dependency-checker": "^3.2.0",