Add set_tag_attribute_values option

[monosans]

Related #10

https://docs.rs/ammonia/latest/ammonia/struct.Builder.html#method.set_tag_attribute_values

[messense]

What's the difference with tag_attribute_values? I'm not sure, could you elaborate?

[monosans]

tag_attribute_values only allows values without forcibly setting them.
set_tag_attribute_values forcibly sets the values. For example, you can use it to add the loading="lazy" attribute to all <img>.