clangd: update current document filter after initialize

This makes sure that the lsp filter gets enabled if a document is opened
before the corresponding clangd server was initialized. This happens
when loading a session with an open document.

Change-Id: I7987ea60c6fca8b5c070af3a7bcd5325667ed0c5
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/clangcodemodel/clangdclient.cpp

@@ -27,6 +27,7 @@
 
 #include "clangcompletioncontextanalyzer.h"
 #include "clangconstants.h"
+#include "clangdlocatorfilters.h"
 #include "clangdqpropertyhighlighter.h"
 #include "clangmodelmanagersupport.h"
 #include "clangpreprocessorassistproposalitem.h"
@@ -1558,6 +1559,9 @@ ClangdClient::ClangdClient(Project *project, const Utils::FilePath &jsonDbDir)
     });
 
     connect(this, &Client::initialized, this, [this] {
+        auto currentDocumentFilter = static_cast<ClangdCurrentDocumentFilter *>(
+            CppEditor::CppModelManager::instance()->currentDocumentFilter());
+        currentDocumentFilter->updateCurrentClient();
         // If we get this signal while there are pending searches, it means that
         // the client was re-initialized, i.e. clangd crashed.