Synced changes with doc team sources.

These are changes and updates merged between GitHub and the AWS doc team.
Looks like the `[]` chars can't be escaped, values that those chars have to be quoted.  So to create a Key of `[Group]`, you have to quote the whole value.  Escaping the quote is so that bash will leave the quotes untouched:

```
# Quote gone:
$ echo --tags Foo="[Bar]"
--tags Foo=[Bar]

# Quotes left alone
```
$ echo --tags Foo=\"[Bar]\"
--tags Foo="[Bar]"
```

So I suppose the text for this should be updated as well, as we're quoting the entire value, not escaping the `[]` chars.