[lldb] Fix ASCII art in CommandObjectSource.h (NFC)

//===-- CommandObjectSource.h.h -----------------------------------*- C++

//-*-===//

//===-- CommandObjectSource.h -----------------------------------*- C++-*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

namespace lldb_private {

// CommandObjectMultiwordSource

class CommandObjectMultiwordSource : public CommandObjectMultiword {

public:

  CommandObjectMultiwordSource(CommandInterpreter &interpreter);