chore: add build:doc script

- Adds a new script `build:doc` that generates the API documentation in
  `package.json`. It runs `@microsoft/api-documenter`.
- Installs `@microsoft/api-documenter` to generate the API
  documentation.

Author: kikuomax

package-lock.json

@@ -11,6 +11,7 @@
   ],
   "scripts": {
     "build": "rollup -c && api-extractor run --local",
+    "build:doc": "npm run build && api-documenter markdown --input-folder temp --output-folder api-docs/markdown",
     "tsc": "tsc",
     "prepare": "npm run build",
     "test": "echo \"Error: no test specified\" && exit 1"
@@ -22,6 +23,7 @@
   "license": "MIT",
   "devDependencies": {
     "@mapbox/unitbezier": "^0.0.1",
+    "@microsoft/api-documenter": "^7.19.7",
     "@microsoft/api-extractor": "^7.28.6",
     "@rollup/plugin-typescript": "^8.3.4",
     "@types/geojson": "^7946.0.10",