Add doc

src/Features/CSharp/Portable/IntroduceVariable/CSharpIntroduceVariableService_IntroduceLocal.cs

@@ -49,6 +49,9 @@ internal partial class CSharpIntroduceVariableService
                         null,
                         SyntaxFactory.EqualsValueClause(expression.WithoutTrivia())))));
 
+            // If we're inserting into a multi-line parent, then add a newline after the local-var
+            // we're adding.  That way we don't end up having it and the starting statement be on
+            // the same line (which will cause indentation to be computed incorrectly).
             var text = await document.Document.GetTextAsync(cancellationToken).ConfigureAwait(false);
             if (!text.AreOnSameLine(containerToGenerateInto.GetFirstToken(), containerToGenerateInto.GetLastToken()))
             {