DocumentLocatorFilter: Get rid of the arg from c'tor

It's always LanguageClientManager::instance().
Pimpl LanguageClientManager's filters, so that they are
constructed after the managerInstance is being assigned.

Change-Id: Ib1f6f0c96d57d0e4cb7332ce322f6c4e9ef9fdb1
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/clangcodemodel/clangdlocatorfilters.cpp

@@ -192,7 +192,6 @@ class LspCurrentDocumentFilter : public DocumentLocatorFilter
 {
 public:
     LspCurrentDocumentFilter()
-        : DocumentLocatorFilter(LanguageClientManager::instance())
     {
         setId({});
         setDisplayName({});

src/plugins/clangcodemodel/clangmodelmanagersupport.cpp

@@ -27,6 +27,7 @@
 #include <cppeditor/editordocumenthandle.h>
 
 #include <languageclient/languageclientmanager.h>
+#include <languageclient/locatorfilter.h>
 
 #include <texteditor/quickfix.h>