Fixed broken link

## What changes were proposed in this pull request?

I fixed some incorrect formatting on a link in the docs

## How was this patch tested?

I looked at the markdown preview before and after, and the link was fixed

Before:
<img width="593" alt="screen shot 2017-06-08 at 6 37 32 pm" src="https://user-images.githubusercontent.com/17733030/26956272-a62cd558-4c79-11e7-862f-9d0e0184b18a.png">
After:
<img width="587" alt="screen shot 2017-06-08 at 6 37 44 pm" src="https://user-images.githubusercontent.com/17733030/26956276-b1135ef6-4c79-11e7-8028-84d19c392fda.png">

Author: Corey Woodfield <coreywoodfield@gmail.com>

Closes #18246 from coreywoodfield/master.

docs/running-on-mesos.md

@@ -156,7 +156,7 @@ passing in the Mesos master URL (e.g: mesos://host:5050). This starts the `Mesos
 If you like to run the `MesosClusterDispatcher` with Marathon, you need to run the `MesosClusterDispatcher` in the foreground (i.e: `bin/spark-class org.apache.spark.deploy.mesos.MesosClusterDispatcher`). Note that the `MesosClusterDispatcher` not yet supports multiple instances for HA.
 
 The `MesosClusterDispatcher` also supports writing recovery state into Zookeeper. This will allow the `MesosClusterDispatcher` to be able to recover all submitted and running containers on relaunch.   In order to enable this recovery mode, you can set SPARK_DAEMON_JAVA_OPTS in spark-env by configuring `spark.deploy.recoveryMode` and related spark.deploy.zookeeper.* configurations.
-For more information about these configurations please refer to the configurations (doc)[configurations.html#deploy].
+For more information about these configurations please refer to the configurations [doc](configurations.html#deploy).
 
 From the client, you can submit a job to Mesos cluster by running `spark-submit` and specifying the master URL
 to the URL of the `MesosClusterDispatcher` (e.g: mesos://dispatcher:7077). You can view driver statuses on the