[kcmkwin/compositing] Use ellipsis in Desktop Effects kcm

Summary: This patch introduces the ellipsis used in Krunner, Kicker, Kickoff and Clipboard to Desktop Effects (Kwin).

Test Plan:
Before: {F6522181}
After: {F6522182}

Reviewers: ngraham, #vdg, #kwin, davidedmundson

Reviewed By: ngraham, #vdg, #kwin, davidedmundson

Subscribers: kwin

Tags: #kwin

Maniphest Tasks: T10258

Differential Revision: https://phabricator.kde.org/D17937

kcmkwin/kwincompositing/qml/EffectView.qml

@@ -72,7 +72,7 @@ Rectangle {
             QQC2.TextField {
                 // TODO: needs clear button, missing in Qt
                 id: searchField
-                placeholderText: i18n("Search")
+                placeholderText: i18n("Search...")
                 Layout.fillWidth: true
                 focus: true
             }