An optimized string type for unique names.
[StringName]s are immutable strings designed for general-purpose represention of unique names. [StringName] ensures that only one instance of a given name exists (so two [StringName]s with the same value are the same object). Comparing them is much faster than with regular [String]s, because only the pointers are compared, not the whole strings.
Creates a new [StringName] from the given [String].