Synced changes with doc team sources.

These are changes and updates merged between GitHub and the AWS doc team.
Looks like this has found a bug in our shorthand syntax parser.  The actual syntax is to just quote the entire value:

```
--tags Key=\"[Group]\",Value=test
```

I've filed https://github.com/aws/aws-cli/issues/876 to track this, but in the meantime, I'll go ahead and update this example to just be:

```
aws ec2 create-tags --resources i-1a2b3c4d --tags Key=\"[Group]\",Value=test
```

Same for the examples below.  I'll cc you on the commits.