Modernize code

src/editor/codec/codecaction.cpp

@@ -93,7 +93,7 @@ static QString selectCharset(KSelectAction *root, const QString &encoding)
             }
         }
     }
-    return QString();
+    return {};
 }
 
 void CodecAction::setCharset(const QByteArray &charset)

src/kontactplugin/summary/kcmkontactsummary.cpp

@@ -54,7 +54,7 @@ public:
         } else if (column == 1) {
             return mInfo.comment();
         } else {
-            return QString();
+            return {};
         }
     }
 

src/kontactplugin/summary/summaryview_part.cpp

@@ -539,5 +539,5 @@ QString SummaryViewPart::widgetName(QWidget *widget) const
         }
     }
 
-    return QString();
+    return {};
 }

src/sieveimapinterface/kmsieveimappasswordprovider.cpp

@@ -37,5 +37,5 @@ QString KMSieveImapPasswordProvider::walletPassword(const QString &identifier)
         }
     }
 
-    return QString();
+    return {};
 }

src/undostack.cpp

@@ -48,7 +48,7 @@ QString UndoStack::undoInfo() const
         UndoInfo *info = mStack.first();
         return info->moveToTrash ? i18n("Move To Trash") : i18np("Move Message", "Move Messages", info->items.count());
     } else {
-        return QString();
+        return {};
     }
 }