This dropped RSS (memory usage) from 4GB to 1.5GB when compiling.
The extra `match` could impact performance but not too concerned since
the default is to not look within vars.
This is mostly to give implementation flexibility for changing out how
we store the data to reduce compilation memory usage.
This does have performance impact, jumping from ~220ns to ~320ns for a
dict lookup, according to our micro benchmarks.
The goal is to be as accepting and unobtrusive to new code bases as
possible. To this end, we correct typos into the closest english
dialect.
If someone wants to opt-in, they can have typos correct to a specific
english dialect.
Fixes#52Fixes#22
