Minor documentation additions

src/private/queues/linked.nim

@@ -11,11 +11,15 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+## A deque implemented on top of a doubly linked list
+
 import strformat
 
 
 type
-    DequeNode*[T] = ref object
+    DequeNode[T] = ref object
+        ## Linked list node
         next: DequeNode[T]
         prev: DequeNode[T]
         val: T