Fix several clazy issue:

* Missing reference in range-for with non trivial type [-Wclazy-range-loop-reference]

src/Gui/ViewProviderLink.cpp

@@ -646,7 +646,7 @@ public:
             dot = next;
         }
 
-        for(auto v : nodeMap) {
+        for(const auto& v : nodeMap) {
             if(v.second->getDetail(true,type,subname,det,path))
                 return true;
         }