Add missing override on destructor

korganizer/plugins/picoftheday/picoftheday.h

@@ -47,7 +47,7 @@ class POTDElement : public StoredElement
 
 public:
     POTDElement(const QString &id, QDate date, QSize initialThumbSize);
-    ~POTDElement()
+    ~POTDElement() override
     {
     }
 

plugins/messageviewerheaderplugins/briefheaderstyleplugin/briefheaderstrategy.h

@@ -15,7 +15,7 @@ class BriefHeaderStrategy : public HeaderStrategy
 {
 public:
     BriefHeaderStrategy();
-    ~BriefHeaderStrategy()
+    ~BriefHeaderStrategy() override
     {
     }
 

plugins/messageviewerheaderplugins/grantleeheaderstyleplugin/grantleeheaderstrategy.h

@@ -14,7 +14,7 @@ class GrantleeHeaderStrategy : public HeaderStrategy
 {
 public:
     GrantleeHeaderStrategy();
-    ~GrantleeHeaderStrategy();
+    ~GrantleeHeaderStrategy() override;
 
 public:
     const char *name() const override

plugins/messageviewerheaderplugins/standardsheaderstyleplugin/standardheaderstrategy.h

@@ -20,7 +20,7 @@ class StandardHeaderStrategy : public HeaderStrategy
 {
 public:
     StandardHeaderStrategy();
-    ~StandardHeaderStrategy();
+    ~StandardHeaderStrategy() override;
 
 public:
     const char *name() const override