_StoredAttribute
An internal type representing a type-erased HTML attribute.
struct _StoredAttributeThis type is used to store HTML attributes and their values of an element. It supports different types of values like plain strings, styles, and classes, and provides different merge strategies when combining attributes.
The merge strategies control how attributes with the same name are combined:
.appendValue: Appends values with a separator (default is space).replaceValue: Replaces any existing value.ignoreIfSet: Keeps the existing value if present