clang-tidy: Use default function declarations

run-clang-tidy -header-filter='.*' -checks='-*,modernize-use-equals-default' -fix

taglib/xm/xmfile.cpp

@@ -70,9 +70,7 @@ namespace
 class Reader
 {
 public:
-  virtual ~Reader()
-  {
-  }
+  virtual ~Reader() = default;
 
   /*!
    * Reads associated values from \a file, but never reads more