lib: include return types in JSDoc

Add types to @returns JSDoc annotations where the type is missing.

PR-URL: #41130
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

lib/internal/blob.js

@@ -129,7 +129,7 @@ class Blob {
    *   endings? : string,
    *   type? : string,
    * }} [options]
-   * @returns
+   * @constructs {Blob}
    */
   constructor(sources = [], options = {}) {
     emitExperimentalWarning('buffer.Blob');

lib/internal/fs/utils.js

@@ -525,7 +525,7 @@ Stats.prototype._checkModeProperty = function(property) {
 /**
  * @param {Float64Array | BigUint64Array} stats
  * @param {number} offset
- * @returns
+ * @returns {BigIntStats | Stats}
  */
 function getStatsFromBinding(stats, offset = 0) {
   if (isBigUint64Array(stats)) {

lib/internal/modules/esm/resolve.js

@@ -588,7 +588,7 @@ function resolvePackageTarget(packageJSONUrl, target, subpath, packageSubpath,
  * @param {Exports} exports
  * @param {URL} packageJSONUrl
  * @param {string | URL | undefined} base
- * @returns
+ * @returns {boolean}
  */
 function isConditionalExportsMainSugar(exports, packageJSONUrl, base) {
   if (typeof exports === 'string' || ArrayIsArray(exports)) return true;
@@ -701,7 +701,7 @@ function patternKeyCompare(a, b) {
  * @param {string} name
  * @param {string | URL | undefined} base
  * @param {Set<string>} conditions
- * @returns
+ * @returns {URL}
  */
 function packageImportsResolve(name, base, conditions) {
   if (name === '#' || StringPrototypeStartsWith(name, '#/') ||

lib/internal/per_context/primordials.js

@@ -404,7 +404,7 @@ primordials.PromisePrototypeCatch = (thisPromise, onRejected) =>
  * @param {Promise<any>} thisPromise
  * @param {() => void) | undefined | null} onFinally The callback to execute
  *        when the Promise is settled (fulfilled or rejected).
- * @returns A Promise for the completion of the callback.
+ * @returns {Promise} A Promise for the completion of the callback.
  */
 primordials.SafePromisePrototypeFinally = (thisPromise, onFinally) =>
   // Wrapping on a new Promise is necessary to not expose the SafePromise

lib/internal/webstreams/adapters.js

@@ -578,7 +578,7 @@ function newReadableWritablePairFromDuplex(duplex) {
  *   objectMode? : boolean,
  *   signal? : AbortSignal,
  * }} [options]
- * @returns
+ * @returns {Duplex}
  */
 function newStreamDuplexFromReadableWritablePair(pair = {}, options = {}) {
   validateObject(pair, 'pair');

lib/querystring.js

@@ -191,7 +191,7 @@ function stringifyPrimitive(v) {
 /**
  * @param {string | number | bigint | boolean} v
  * @param {(v: string) => string} encode
- * @returns
+ * @returns {string}
  */
 function encodeStringified(v, encode) {
   if (typeof v === 'string')