Minor Mermaid fix for older versions

src/graph/GraphView.cpp

@@ -151,7 +151,7 @@ void Aidge::GraphView::save(const std::string& path, bool verbose, bool showProd
     size_t inputIdx = 0;
     for (auto input : mInputNodes) {
       if (input.first != nullptr) {
-        fmt::print(fp.get(), "input{}((in#{})):::inputCls--->|→{}|{}_{}\n", inputIdx, inputIdx,
+        fmt::print(fp.get(), "input{}((in#{})):::inputCls--->|\"→{}\"|{}_{}\n", inputIdx, inputIdx,
                     input.second, input.first->type(), namePtrTable.at(input.first));
       }
       else {