chore: Use Typescript to lint JSDoc annotations (#986)

This patch starts using typescript to lint JSDoc annotations.

Note: this uses typescript's bleeding edge. We should migrate to stable once
it has all the necessary bugfixes.

References #65.

lib/Multimap.js

@@ -14,19 +14,11 @@
  * limitations under the License.
  */
 
-/**
- * @template K, V
- */
 class Multimap {
   constructor() {
-    /** @type {!Map<K, !Set<!V>>} */
     this._map = new Map();
   }
 
-  /**
-   * @param {K} key
-   * @param {V} value
-   */
   set(key, value) {
     let set = this._map.get(key);
     if (!set) {
@@ -36,10 +28,6 @@ class Multimap {
     set.add(value);
   }
 
-  /**
-   * @param {K} key
-   * @return {!Set<!V>}
-   */
   get(key) {
     let result = this._map.get(key);
     if (!result)
@@ -47,19 +35,10 @@ class Multimap {
     return result;
   }
 
-  /**
-   * @param {K} key
-   * @return {boolean}
-   */
   has(key) {
     return this._map.has(key);
   }
 
-  /**
-   * @param {K} key
-   * @param {V} value
-   * @return {boolean}
-   */
   hasValue(key, value) {
     const set = this._map.get(key);
     if (!set)
@@ -74,11 +53,6 @@ class Multimap {
     return this._map.size;
   }
 
-  /**
-   * @param {K} key
-   * @param {V} value
-   * @return {boolean}
-   */
   delete(key, value) {
     const values = this.get(key);
     const result = values.delete(value);
@@ -87,17 +61,10 @@ class Multimap {
     return result;
   }
 
-  /**
-   * @param {K} key
-   */
   deleteAll(key) {
     this._map.delete(key);
   }
 
-  /**
-   * @param {K} key
-   * @return {?V} value
-   */
   firstValue(key) {
     const set = this._map.get(key);
     if (!set)
@@ -105,16 +72,10 @@ class Multimap {
     return set.values().next().value;
   }
 
-  /**
-   * @return {K}
-   */
   firstKey() {
     return this._map.keys().next().value;
   }
 
-  /**
-   * @return {!Array<!V>}
-   */
   valuesArray() {
     const result = [];
     for (const key of this._map.keys())
@@ -122,9 +83,6 @@ class Multimap {
     return result;
   }
 
-  /**
-   * @return {!Array<!K>}
-   */
   keysArray() {
     return Array.from(this._map.keys());
   }