LibWeb: Mark compilation-unit-only functions as static

This enables a nice warning in case a function becomes dead code. Also, in the
case of {Event,Node}WrapperFactory.cpp, the corresponding header was forgotten.
This would cause an issue later when we enable -Wmissing-declarations.

Is my clang-format misconfigured? Why is the diff for NodeWrapperFactory.cpp
so large?

Libraries/LibWeb/CodeGenerators/WrapperGenerator.cpp

@@ -116,7 +116,7 @@ struct Interface {
     String fully_qualified_name;
 };
 
-OwnPtr<Interface> parse_interface(const StringView& input)
+static OwnPtr<Interface> parse_interface(const StringView& input)
 {
     auto interface = make<Interface>();
 
@@ -339,7 +339,6 @@ int main(int argc, char** argv)
         interface->fully_qualified_name = interface->name;
     }
 
-
 #if 0
     dbg() << "Attributes:";
     for (auto& attribute : interface->attributes) {