Fix documentation/comments for Model.findById

lib/model.js

@@ -1440,19 +1440,19 @@ Model.$findSeparate = function(results, options) {
 };
 
 /**
-* Search for a single instance by its primary key. This applies LIMIT 1, so the listener will always be called with a single instance.
+* Search for a single instance by its primary key.
 *
-* @param  {Number|String|Buffer}      [options] A hash of options to describe the scope of the search, or a number to search by id.
-* @param  {Object}             '      [options]
+* @param  {Number|String|Buffer}      id The value of the desired instance's primary key.
+* @param  {Object}                    [options]
 * @param  {Transaction}               [options.transaction] Transaction to run query under
 * @param  {String}                    [options.searchPath=DEFAULT] An optional parameter to specify the schema search_path (Postgres only)
 *
-* @see {Model#findAll}           for an explanation of options
+* @see {Model#findAll}           for a full explanation of options
 * @return {Promise<Instance>}
 * @alias findByPrimary
 */
 Model.prototype.findById = function(param, options) {
-  // For sanity findById will never return if no options are passed
+  // return Promise resolved with null if no arguments are passed
   if ([null, undefined].indexOf(param) !== -1) {
     return Promise.resolve(null);
   }