docs(guide/providers): note that services can create functions

The conclusion table incorrectly states that services can not create functions.
New table row added to separate "can create functions" and "can create primitives".

Author: mattduggan

docs/content/guide/providers.ngdoc

@@ -409,7 +409,15 @@ To wrap it up, let's summarize the most important points:
   <td class="success">yes\*\*</td>
 </tr>
 <tr>
-  <td>can create functions/primitives</td>
+  <td>can create functions</td>
+  <td class="success">yes</td>
+  <td class="success">yes</td>
+  <td class="success">yes</td>
+  <td class="success">yes</td>
+  <td class="success">yes</td>
+</tr>
+<tr>
+  <td>can create primitives</td>
   <td class="success">yes</td>
   <td class="error">no</td>
   <td class="success">yes</td>