Remove eslint "valid-jsdoc" rules/fix linting errors

Our eslintrc file extends "wikimedia/client" which already includes all
of the previously listed jsdoc rules [1]. Therefore, we were clobbering
this much more thorough list.

This commit removes this clobbering and enables a much more extensive
list of jsdoc rules. Additionally, downloadPageActions was made to
conform to the rules.

[1] 07320f16ae/common.json (L99-L137)

Bug: T239269
Change-Id: I19c09054ba0bf2746ac78befc1b44426352113ec

.eslintrc.json

@@ -36,20 +36,6 @@
 				"message": "The method `always` if used with Deferred objects is incompatible with ES6 Promises. Please use `then`."
 			}
 		],
-		"valid-jsdoc": [
-			"error",
-			{
-				"requireParamDescription": false,
-				"requireReturnDescription": false,
-				"requireReturn": false,
-				"preferType": {
-					"Boolean": "boolean",
-					"Number": "number",
-					"object": "Object",
-					"String": "string"
-				}
-			}
-		],
 		"object-property-newline": "error",
 		"no-use-before-define": "off",
 		"no-underscore-dangle": "off"

resources/skins.minerva.scripts/downloadPageAction.js

@@ -106,7 +106,7 @@
 	 * Expects to be run in the context of an icon using `Function.bind`
 	 *
 	 * @param {Icon} spinner
-	 * @returns {function}
+	 * @return {Function}
 	 */
 	function getOnClickHandler( spinner ) {
 		return function () {
@@ -122,7 +122,7 @@
 	 * @param {number[]} supportedNamespaces
 	 * @param {Window} [windowObj] window object
 	 * @param {boolean} [hasText] Use icon + button style.
-	 * @returns {jQuery.Object|null}
+	 * @return {jQuery.Object|null}
 	 */
 	function downloadPageAction( page, supportedNamespaces, windowObj, hasText ) {
 		var