The Superset method on Resources used to return a string in the format of “[resource name] exhausted”.
This was leading to the output in plan/create job API DimensionExhausted to return keys like
```
"DimensionExhausted": {"cpu exhausted": 1}
```
This was not anywhere documented, however, one of the examples on the website showed it like this.

The other side effect of this is that the CLI formats the strings from the name of the key leading to output like
```
* Dimension "cpu exhausted" exhausted on 1 nodes
```

This PR fixes an incorrect placement of the update stanza in the task
and also links from the env stanza into an example of using the template
block to generate dynamic environment variables.

* Update operating a job, upgrade guide

This PR updates the guide for updating a job to reflect the changes in
Nomad 0.6

* Feedback changes

* Feedback

* Feedback

Previously, -tail is erroneously documented as -f and -f and -n are not documented at all. 

This patch fixes both.

Remove the reference to `http://localhost:4567` within the Rolling Update
strategy documentation and fix the link to the `nomad plan` command
documentation.