Remove trailing space after <enter> between arguments (etc.)

[dpoeschl]

Inspired by all of the trailing spaces that were removed by the CodeFormatter in #933

1. Paste C#:

class C
{
    void M(string a, string b)
    {
        M("Dog", "Cat");
    }
}

1. Place the caret before "Cat" and press enter

Expected: The "Cat" argument is moved to the next line and the previous line's trailing space is removed. Actual: The trailing space is left on the previous line.

Dev12 had the same behavior, so this is not a regression.

[alexsorokoletov]

would be somewhere in Workspaces\CSharpWorkspaces\Formatting\Rules @Pilchie

[Pilchie]

There is an existing .editorconfig rule for this. We should look at obeying it.