Search for syntax-highlighting qml module

It's an optional part of syntax-highlighting so just searching for
the it is not enough we need to make sure to have the qml module.
Also don't link to it, we only need it at runtime.

CMakeLists.txt

@@ -72,10 +72,11 @@ if(ANDROID)
     )
 else()
     find_package(Qt5 ${QT_MIN_VERSION} COMPONENTS Widgets)
-    find_package(KF5 ${KF5_MIN_VERSION} REQUIRED COMPONENTS QQC2DesktopStyle ConfigWidgets KIO WindowSystem Sonnet SyntaxHighlighting)
+    find_package(KF5 ${KF5_MIN_VERSION} REQUIRED COMPONENTS QQC2DesktopStyle ConfigWidgets KIO WindowSystem Sonnet)
     set_package_properties(KF5QQC2DesktopStyle PROPERTIES
         TYPE RUNTIME
     )
+    ecm_find_qmlmodule(org.kde.syntaxhighlighting 1.0)
 endif()
 
 if (NOT ANDROID AND NOT WIN32 AND NOT APPLE)