[Typescript] add missing typeRoots config on tsconfig (#21824)

* add missing typeRoots config on tsconfig

* add samples

* Apply suggestion from @macjohnny

Co-authored-by: Esteban Gehring <[email protected]>

* update samples

---------

Co-authored-by: Esteban Gehring <[email protected]>

Author: nikatlas

modules/openapi-generator/src/main/resources/typescript/tsconfig.mustache

@@ -11,6 +11,9 @@
     {{/supportsES6}}
     "moduleResolution": "node",
     "declaration": true,
+    "typeRoots": [
+        "node_modules/@types"
+    ],
 
     /* Additional Checks */
      "noUnusedLocals": false,                     /* Report errors on unused locals. */ // TODO: reenable (unused imports!)