add support for typescript-style docstrings

this change adds [jsdoc-ts-utils](https://npm.im/jsdoc-ts-utils), which I have had success using in [mrca](https://npm.im/mrca).  it allows us to use the `import()` syntax to reference types in other modules, and other things that make working in a TS-language-server-enabled editor much nicer.

it does not support _all_ of the stuff TS does, but at least helps.

this should not change the API documentation output

(at least until we start using the new supported features)

Signed-off-by: Christopher Hiller <boneskull@boneskull.com>

jsdoc.conf.json

@@ -15,7 +15,7 @@
     "tutorials": "docs/api-tutorials",
     "verbose": true
   },
-  "plugins": ["plugins/markdown"],
+  "plugins": ["./node_modules/jsdoc-ts-utils", "plugins/markdown"],
   "source": {
     "include": ["lib/", "./docs/API.md", "bin"]
   },