Add note to big upload docs that those are not relevant for the sync client?

[ghost]

Hi,

while doing #930 i've noticed that this page is describing the possible limitations of ownCloud with large files.

But those are only relevant for uploads via the WebGUI and/or the WebDAV interface via 3rdparty tools. The sync client itself is doing chunked uploads with files of a 10MB size.

Any opinions if it could be useful to add a short note about this?