Adjust comments during field rename

[jaredpar]

Consider the following field definition:

class C
{
  private int _field1  // Comment
  private int field2;   // Comment
}

After formatting we end up with:

class C
{
  private int _field1  // Comment
  private int _field2;   // Comment
}

Before the tool ran the comments were aligned and after they are not. I think the tool should account for this by detecting this pattern and adjusting the white space after the definition and before the comment to keep the spacing the same.