LibJS: run clang-format on all the files

Author: https://github.com/emanuele6
Commit: 8bd9f7e50e
Pull-request: https://github.com/SerenityOS/serenity/pull/2098
Reviewed-by: https://github.com/awesomekling

Libraries/LibJS/Heap/Heap.cpp

@@ -198,7 +198,7 @@ Cell* Heap::cell_from_possible_pointer(FlatPtr pointer)
 
 class MarkingVisitor final : public Cell::Visitor {
 public:
-    MarkingVisitor() {}
+    MarkingVisitor() { }
 
     virtual void visit_impl(Cell* cell)
     {