add explicit to constructor with 1 argument

src/AppColorSchemeChooser.h

@@ -26,7 +26,7 @@ class KActionCollection;
 class KONSOLEPRIVATE_EXPORT AppColorSchemeChooser : public QAction
 {
 public:
-    AppColorSchemeChooser(QObject *parent);
+    explicit AppColorSchemeChooser(QObject *parent);
 
     QString currentSchemeName() const;
 

src/plugins/SSHManager/sshmanagerfiltermodel.h

@@ -14,7 +14,7 @@ class SSHManagerFilterModel : public QSortFilterProxyModel
 {
     Q_OBJECT
 public:
-    SSHManagerFilterModel(QObject *parent);
+    explicit SSHManagerFilterModel(QObject *parent);
     bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const override;
     void setInvertFilter(bool invert);
 

src/terminalDisplay/TerminalBell.h

@@ -20,7 +20,7 @@ class TerminalBell : public QObject
     Q_OBJECT
 
 public:
-    TerminalBell(Enum::BellModeEnum bellMode);
+    explicit TerminalBell(Enum::BellModeEnum bellMode);
     void bell(QWidget *td, const QString &message, bool terminalHasFocus);
 
     /**