'Building the files object dynamically' should be array?

(I was going to submit a PR, but after lots of searching I still couldn't figure out where the actual content of the docs was hiding.)

New to Grunt; noticed what I believe to be an error while studying the docs.

The 'Files Object' format is documented here http://gruntjs.com/configuring-tasks#files-object-format, and looks like this:

```
files: { 'src': 'dest' }
```

The 'Files Array' format is documented here http://gruntjs.com/configuring-tasks#files-array-format, and looks like this:

```
files: [
{src: '...', dest: '...'},
]
```

Further down, there's a section called 'Building the files object dynamically': http://gruntjs.com/configuring-tasks#building-the-files-object-dynamically

However, the example given resembles the Files Array format, not Files Object:

```
files: [
{
expand: true,
cwd: 'lib/',
src: ['**/*.js'],
dest: 'build/',
ext: '.min.js',
},
]
```

Shouldn't the entire section be called 'Building the files _array_ dynamically'?

If so, you will also need to update the reference to it in the explanation of the 'expand' option in this section: http://gruntjs.com/configuring-tasks#files