Annotate support label

allow "kubectl annotate pods -l app=nginx"

docs/user-guide/kubectl/kubectl_annotate.md

@@ -88,6 +88,7 @@ $ kubectl annotate pods foo description-
       --output-version="": Output the formatted object with the given version (default api-version).
       --overwrite[=false]: If true, allow annotations to be overwritten, otherwise reject annotation updates that overwrite existing annotations.
       --resource-version="": If non-empty, the annotation update will only succeed if this is the current resource-version for the object. Only valid when specifying a single resource.
+  -l, --selector="": Selector (label query) to filter on
   -a, --show-all[=false]: When printing, show all resources (default hide terminated pods.)
       --sort-by="": If non-empty, sort list types using this field specification.  The field specification is expressed as a JSONPath expression (e.g. 'ObjectMeta.Name'). The field in the API resource specified by this JSONPath expression must be an integer or a string.
       --template="": Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].
@@ -125,7 +126,7 @@ $ kubectl annotate pods foo description-
 
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra on 19-Nov-2015
+###### Auto generated by spf13/cobra on 24-Nov-2015
 
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