Boa's **`boa_interner`** is a string interner for compiler performance.
# Crate Overview
The idea behind using a string interner is that in most of the code, strings such as
identifiers and literals are often repeated. This causes extra burden when comparing them and
storing them. A string interner stores a unique `usize` symbol for each string, making sure
that there are no duplicates. This makes it much easier to compare, since it's just comparing
to `usize`, and also it's easier to store, since instead of a heap-allocated string, you only
need to store a `usize`. This reduces memory consumption and improves performance in the
compiler.