Add example of simple multiple file upload in documentation

[zxcq544]

At ​https://docs.djangoproject.com/en/1.9/topics/http/file-uploads/ we could add simple example of multiple file upload:

In views.py

def handle_uploaded_files(files):
    for i in files:
        with open('uploads/' + i.name, 'wb+') as destination:
            for chunk in i.chunks():
                destination.write(chunk)


def upload_file(request):
    if request.method == 'POST':
        handle_uploaded_files(request.FILES.getlist('files[]'))        
    return render(request, 'upload.html')

In upload.html

<form method="post" enctype="multipart/form-data">
    {% csrf_token %}
    <input type="file" name="files[]" multiple>
    <input type="submit" value="Send">
</form>

[Berker Peksag]

​https://github.com/django/django/pull/6603

[Tim Graham <timograham@…>]

In 54febdb8:

Fixed #26604 -- Added a multiple file upload example to topics/http/file-uploads.txt.

[Tim Graham <timograham@…>]

In 7407440:

[1.9.x] Fixed #26604 -- Added a multiple file upload example to topics/http/file-uploads.txt.

Backport of 54febdb8be7c9793caae9c781f4d6b7cbbdcd900 from master

[Tim Graham <timograham@…>]

In 27983d82:

[1.10.x] Fixed #26604 -- Added a multiple file upload example to topics/http/file-uploads.txt.

Backport of 54febdb8be7c9793caae9c781f4d6b7cbbdcd900 from master