Fix sidebar pending queries counter after 738c10d

The optimization changes of 738c10d could leave the m_pendingQueries
counter in inconsistent change, because it was resetted to 0 too early.
In practice, this would cause OnQueriesFinished() to be called when they
weren't yet finished.

src/sidebar.cpp

@@ -475,7 +475,6 @@ void SuggestionsSidebarBlock::ReportError(SuggestionsBackend*, std::exception_pt
 
 void SuggestionsSidebarBlock::ClearSuggestions()
 {
-    m_pendingQueries = 0;
     m_suggestions.clear();
     UpdateSuggestionsMenu();
     UpdateVisibility();
@@ -661,6 +660,8 @@ void SuggestionsSidebarBlock::UpdateSuggestionsForItem(CatalogItemPtr item)
         return;
     }
 
+    m_pendingQueries = 0;
+
     auto srclang = m_parent->GetCurrentSourceLanguage();
     auto lang = m_parent->GetCurrentLanguage();
     if (!srclang.IsValid() || !lang.IsValid() || srclang == lang)