fix typos

Signed-off-by: allencloud <allen.sun@daocloud.io>

cluster/event.go

@@ -26,7 +26,7 @@ type EventHandlers struct {
 	eventHandlers map[EventHandler]struct{}
 }
 
-// NewEventHandlers returns a EventHandlers
+// NewEventHandlers returns an EventHandlers
 func NewEventHandlers() *EventHandlers {
 	return &EventHandlers{
 		eventHandlers: make(map[EventHandler]struct{}),

cluster/mesos/task/tasks.go

@@ -32,7 +32,7 @@ func (t *Tasks) Add(task *Task) {
 	}
 }
 
-// Remove an Task from the tasks
+// Remove a Task from the tasks
 func (t *Tasks) Remove(tasks ...*Task) {
 	t.Lock()
 	t.remove(tasks...)

docs/discovery.md

@@ -107,7 +107,7 @@ store.
 
 You can use a static file or list of nodes for your discovery backend. The file must be stored on a host that is accessible from the Swarm manager. You can also pass a node list as an option when you start Swarm.
 
-Both the static file and the `nodes` option support a IP address ranges. To specify a range supply a pattern, for example, `10.0.0.[10:200]` refers to nodes starting from `10.0.0.10` to `10.0.0.200`.  For example for the `file` discovery method.
+Both the static file and the `nodes` option support an IP address ranges. To specify a range supply a pattern, for example, `10.0.0.[10:200]` refers to nodes starting from `10.0.0.10` to `10.0.0.200`.  For example for the `file` discovery method.
 
         $ echo "10.0.0.[11:100]:2375"   >> /tmp/my_cluster
         $ echo "10.0.1.[15:20]:2375"    >> /tmp/my_cluster

docs/get-swarm.md

@@ -29,7 +29,7 @@ The first time you use any image, Docker Engine checks to see if you already hav
 
 1. Open a terminal on a host running Engine.
 
-    If you are using Mac or Windows, then you must make sure you have started an Docker Engine host running and pointed your terminal environment to it with the Docker Machine commands. If you aren't sure, you can verify:
+    If you are using Mac or Windows, then you must make sure you have started a Docker Engine host running and pointed your terminal environment to it with the Docker Machine commands. If you aren't sure, you can verify:
 
         $ docker-machine ls
         NAME      ACTIVE   URL          STATE     URL                         SWARM   DOCKER    ERRORS

docs/secure-swarm-tls.md

@@ -35,7 +35,7 @@ The following analogy may be useful. It is common practice that passports are
 used to verify an individual's identity. Passports usually contain a photograph
 and biometric information that identify the owner. A passport also lists the
 country that issued it, as well as *valid from* and *valid to* dates. Digital
-certificates are very similar. The text below is an extract from a a digital
+certificates are very similar. The text below is an extract from a digital
 certificate:
 
 ```

docs/swarm_at_scale/deploy-app.md

@@ -39,7 +39,7 @@ on the Swarm `manager` instance.
     $ eval $(docker-machine env manager)
     ```
 
-    You can create the network on an cluster node at the network is visible on
+    You can create the network on a cluster node at the network is visible on
     them all.
 
 2. Create the `voteapp` container network.