fix: export locals_without_parens from .formatter.exs

[jimsynz]

Fixes #202.

The export key in .formatter.exs was spelled locals_without_parems, so
every downstream package with import_deps: [:bb] resolved an empty list and
mix format added brackets to every DSL call.

The top-level locals_without_parens was spelled correctly, so formatting
inside this repo was never affected — which is why it went unnoticed.

Verification

Tested against bb_servo_pca9685 (which already sets import_deps: [:bb]) by
swapping the fixed and published .formatter.exs into its deps/bb and
clearing cached_dot_formatter between runs:

deps/bb/.formatter.exs	paren-less type :revolute after mix format
as published in v0.25.0	rewritten to type(:revolute)
with this fix	left as type :revolute

The satellite's resolved locals_without_parens goes from 0 to 126 entries.

mix check --no-retry passes, including mix spark.formatter --check — the
Spark task only rewrites the spark_locals_without_parens list, so it doesn't
reintroduce the typo.

Note on scope

The issue's description implies the fix lets a satellite strip existing
brackets. It doesn't: the Elixir formatter only refrains from adding parens
for locals_without_parens entries, and preserves parens already present in
the source. Confirmed in this repo, where type(:revolute) survives
mix format despite the correct top-level key.

So satellites carrying already-bracketed DSL (e.g. bb_servo_pca9685's
test/support/pan_tilt_robot.ex) need a one-off pass to strip them once they
pick up a release with this fix. This PR only stops the formatter fighting
paren-less code from here on.