C# editor insert space when autoformat instead of tab

[egamma]

From @Thaina on March 29, 2016 5:59

I already set a setting as "editor.insertSpaces": false,

But when I trigger autoformat,type } to close block for example, all tab in that block was convert into 4 space

This only happen to C#

Copied from original issue: microsoft/vscode#4729

[DustinCampbell]

This is a duplicate of #93