Debugger: Use override consistently

clang-tidy fixes from modernize-use-override check.

Change-Id: I6a20484716dc5bd84fe9592b40ae57be66fe32bf
Reviewed-by: hjk <hjk@qt.io>

src/plugins/debugger/disassembleragent.h

@@ -43,7 +43,7 @@ class DisassemblerAgent : public QObject
 public:
     // Called from Gui
     explicit DisassemblerAgent(DebuggerEngine *engine);
-    ~DisassemblerAgent();
+    ~DisassemblerAgent() override;
 
     void setLocation(const Location &location);
     const Location &location() const;