[docs] Reorganize other integrations page (#551)

- move all boto integrations under a general heading

Author: Kyle-Verhoog

docs/other_integrations.rst

@@ -1,6 +1,11 @@
 Other Libraries
 ===============
 
+.. _boto:
+
+Boto
+----
+
 .. _aiobotocore:
 
 aiobotocore
@@ -9,14 +14,6 @@ aiobotocore
 .. automodule:: ddtrace.contrib.aiobotocore
 
 
-.. _futures:
-
-Futures
-^^^^^^^
-
-.. automodule:: ddtrace.contrib.futures
-
-
 .. _boto2:
 
 Boto2
@@ -33,23 +30,32 @@ Botocore
 .. automodule:: ddtrace.contrib.botocore
 
 
+
+.. _futures:
+
+Futures
+-------
+
+.. automodule:: ddtrace.contrib.futures
+
+
 .. _celery:
 
 Celery
-^^^^^^
+------
 
 .. automodule:: ddtrace.contrib.celery
 
 .. _httplib:
 
 httplib
-^^^^^^^
+-------
 
 .. automodule:: ddtrace.contrib.httplib
 
 .. _requests:
 
 Requests
-^^^^^^^^
+--------
 
 .. automodule:: ddtrace.contrib.requests