ElidedButton: Make constructor explicit

Prevents implicit conversions to ElidedButton.

Source/Core/DolphinQt2/QtUtils/ElidedButton.h

@@ -9,8 +9,8 @@
 class ElidedButton : public QPushButton
 {
 public:
-  ElidedButton(const QString& text = QStringLiteral(""),
-               Qt::TextElideMode elide_mode = Qt::ElideRight);
+  explicit ElidedButton(const QString& text = QStringLiteral(""),
+                        Qt::TextElideMode elide_mode = Qt::ElideRight);
   Qt::TextElideMode elideMode() const;
   void setElideMode(Qt::TextElideMode elide_mode);