added links to API calls

doc/api/groups.md

@@ -183,10 +183,10 @@ By default, groups only get 20 namespaces at a time because the API results are
 
 To get more (up to 100), pass the following as an argument to the API call:
 ```
-per_page=100
+/groups?per_page=100
 ```
 
 And to switch pages add: 
 ```
-page=2
+/groups?per_page=100&page=2
 ```
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