Core/Utils: Migrate further to Utils::Id

The coreplugin/id.h header is kept for downstream for now.

Change-Id: I8c44590f7b988b3770ecdc177c40783e12353e66
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/coreplugin/find/findplugin.cpp

@@ -38,7 +38,6 @@
 #include <coreplugin/coreconstants.h>
 #include <coreplugin/icontext.h>
 #include <coreplugin/icore.h>
-#include <coreplugin/id.h>
 #include <coreplugin/coreplugin.h>
 
 #include <extensionsystem/pluginmanager.h>
@@ -66,6 +65,7 @@
 Q_DECLARE_METATYPE(Core::IFindFilter*)
 
 using namespace Qt;
+using namespace Utils;
 
 namespace {
     const int MAX_COMPLETIONS = 50;