docs($q): fixup dgeni ngdoc annotations for $q methods

Just a tiny fixup, that's all.

Closes #6317

src/ng/q.js

@@ -189,8 +189,10 @@ function $QProvider() {
 function qFactory(nextTick, exceptionHandler) {
 
   /**
-   * @ngdoc
+   * @ngdoc method
    * @name $q#defer
+   * @function
+   *
    * @description
    * Creates a `Deferred` object which represents a task which will finish in the future.
    *
@@ -344,8 +346,10 @@ function qFactory(nextTick, exceptionHandler) {
 
 
   /**
-   * @ngdoc
+   * @ngdoc method
    * @name $q#reject
+   * @function
+   *
    * @description
    * Creates a promise that is resolved as rejected with the specified `reason`. This api should be
    * used to forward rejection in a chain of promises. If you are dealing with the last promise in
@@ -402,8 +406,10 @@ function qFactory(nextTick, exceptionHandler) {
 
 
   /**
-   * @ngdoc
+   * @ngdoc method
    * @name $q#when
+   * @function
+   *
    * @description
    * Wraps an object that might be a value or a (3rd party) then-able promise into a $q promise.
    * This is useful when you are dealing with an object that might or might not be a promise, or if
@@ -472,8 +478,10 @@ function qFactory(nextTick, exceptionHandler) {
 
 
   /**
-   * @ngdoc
+   * @ngdoc method
    * @name $q#all
+   * @function
+   *
    * @description
    * Combines multiple promises into a single promise that is resolved when all of the input
    * promises are resolved.