Xml formatter should not add a second line

[OleRoss]

Input:

nuget.config:

<?xml version="1.0" encoding="utf-8"?>

<configuration>
  <packageSources>
    <clear />
    <add key="NuGet" value="https://api.nuget.org/v3/index.json" />
  </packageSources>
</configuration>

Output:

<?xml version="1.0" encoding="utf-8"?>


<configuration>
  <packageSources>
    <clear />
    <add key="NuGet" value="https://api.nuget.org/v3/index.json" />
  </packageSources>
</configuration>

Expected behavior:

The formatter should not introduce a new line at lines 2-3.

Run with csharpier 1.2.1