ndb: update outdated documentation for sources

SourcesView has no .details() method.

pyroute2/ndb/source.py

@@ -7,18 +7,29 @@
 starts with one local RTNL source names `localhost`::
 
     >>> ndb = NDB()
-    >>> ndb.sources.details()
-    {'kind': u'local', u'nlm_generator': 1, 'target': u'localhost'}
+    >>> ndb.sources.summary().format("json")
+    [
+        {
+            "name": "localhost",
+            "spec": "{'target': 'localhost', 'nlm_generator': 1}",
+            "state": "running"
+        },
+        {
+            "name": "localhost/nsmanager",
+            "spec": "{'target': 'localhost/nsmanager'}",
+            "state": "running"
+        }
+    ]
     >>> ndb.sources['localhost']
-    [running] <IPRoute {'nlm_generator': 1}>
+    [running] <IPRoute {'target: 'localhost', 'nlm_generator': 1}>
 
 The `localhost` RTNL source starts an additional async cache thread.
 The `nlm_generator` option means that instead of collections the
 `IPRoute` object returns generators, so `IPRoute` responses will not
 consume memory regardless of the RTNL objects number::
 
     >>> ndb.sources['localhost'].nl.link('dump')
-    <generator object _match at 0x7fa444961e10>
+    <generator object RTNL_API.filter_messages at 0x7f61a99a34a0>
 
 See also: :ref:`iproute`