Remove plugin loading using keywords

This was deprecated in during the 5.24 development period. All KDE
consumers are ported away from it. Third parties will get meaningful
runtime messages which instruct them to register the plugins without keywords.

The create overloads which take keywords were already deprecated in KPluginFactory.

src/kcmkwin/kwindecoration/declarative-plugin/previewbridge.cpp

@@ -147,16 +147,7 @@ DecorationButton *PreviewBridge::createButton(KDecoration2::Decoration *decorati
     if (!m_valid) {
         return nullptr;
     }
-    auto button = m_factory->create<KDecoration2::DecorationButton>(parent, QVariantList({QVariant::fromValue(type), QVariant::fromValue(decoration)}));
-#if KCOREADDONS_BUILD_DEPRECATED_SINCE(5, 87)
-    if (!button) {
-        button = m_factory->create<KDecoration2::DecorationButton>(QStringLiteral("button"), parent, QVariantList({QVariant::fromValue(type), QVariant::fromValue(decoration)}));
-        if (button) {
-            qWarning() << "Loading a KDecoration2::DecorationButton using the button keyword is deprecated in KWin 5.23, register the plugin without a keyword instead" << m_plugin;
-        }
-    }
-#endif
-    return button;
+    return m_factory->create<KDecoration2::DecorationButton>(parent, QVariantList({QVariant::fromValue(type), QVariant::fromValue(decoration)}));
 }
 
 void PreviewBridge::configure(QQuickItem *ctx)
@@ -177,18 +168,7 @@ void PreviewBridge::configure(QQuickItem *ctx)
         args.insert(QStringLiteral("theme"), m_theme);
     }
 
-    KCModule *kcm = nullptr;
-
-    kcm = m_factory->create<KCModule>(dialog, QVariantList({args}));
-
-#if KCOREADDONS_BUILD_DEPRECATED_SINCE(5, 87)
-    if (!kcm) {
-        kcm = m_factory->create<KCModule>(QStringLiteral("kcmodule"), dialog, QVariantList({args}));
-        if (kcm) {
-            qWarning() << "Loading a KCModule using the kcmodule keyword is deprecated in KWin 5.23, register the plugin without a keyword instead" << m_theme;
-        }
-    }
-#endif
+    KCModule *kcm = m_factory->create<KCModule>(dialog, QVariantList({args}));
 
     if (!kcm) {
         return;