Fix builds (LMMS#6548)

Add the comment "// namespace lmms" to the closing scope of the lmms
namespaces. The "scripted-checks" are quite strict. Perhaps they should
be renamed to "strict-checks". ;)

Include "cassert" in UpgradeExtendedNoteRange.cpp to hopefully fix the
mingw builds.

src/core/UpgradeExtendedNoteRange.cpp

@@ -27,6 +27,8 @@
 #include <QDomElement>
 
 #include <set>
+#include <cassert>
+
 
 namespace lmms
 {
@@ -428,4 +430,4 @@ void UpgradeExtendedNoteRange::upgrade()
 	}
 }
 
-}
+} // namespace lmms

src/core/UpgradeExtendedNoteRange.h

@@ -42,6 +42,6 @@ class UpgradeExtendedNoteRange
 	QDomElement & m_domElement;
 };
 
-}
+} // namespace lmms
 
 #endif // LMMS_UPGRADEEXTENDEDNOTERANGE_H