LanguageClient: Do not cancel search on empty result list

... for a rename request.
Instead, simply finish the search normally, leading to a "no matches
found" message rather than the misleading "search canceled".
But do cancel the search on an actual error.

Change-Id: I10401466bb4d81d53d26b8dc08bfed91db86cd5a
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/languageclient/languageclientsymbolsupport.cpp

@@ -384,7 +384,7 @@ void SymbolSupport::handleRenameResponse(Core::SearchResult *search,
         search->setSearchAgainEnabled(false);
         search->finishSearch(false);
     } else {
-        search->finishSearch(true);
+        search->finishSearch(error.has_value());
     }
 }