Remove annoying print in producer @olivierbichler.

include/aidge/operator/Producer.hpp

@@ -105,7 +105,7 @@ public:
     void forward() override final;
 
     void backward() override final {
-        fmt::print("Basic Producer backward() function.\n");
+        // fmt::print("Basic Producer backward() function.\n");
     }
     void setOutput(const Aidge::IOIndex_t outputIdx, std::shared_ptr<Aidge::Data>&& data) override {
         if (getAttr<ProdAttr::Constant>()) {

src/operator/Producer.cpp

@@ -72,9 +72,9 @@ void Aidge::Producer_Op::forward() {
     if (!backend().empty()) {
         mImpl->forward();
     }
-    else {
-        fmt::print("Basic Producer forward() function.\n");
-    }
+    // else {
+    //     fmt::print("Basic Producer forward() function.\n");
+    // }
 
     runHooks();
 }