style: remove em dashes from rustac notebook

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: aboydnw

quickstarts/rustac.ipynb

@@ -159,7 +159,7 @@
    "source": [
     "## Write results without materializing Python objects",
     "",
-    "For bulk work, skip the round-trip through Python dictionaries. `search_to_arrow` takes the same arguments as `search` and returns an Arrow table. It is backed by `arro3` (rustac's Arrow runtime), so adopt it into PyArrow with `pa.table(...)` \u2014 a zero-copy hand-off \u2014 before writing it to a new Parquet file.",
+    "For bulk work, skip the round-trip through Python dictionaries. `search_to_arrow` takes the same arguments as `search` and returns an Arrow table. It is backed by `arro3` (rustac's Arrow runtime), so adopt it into PyArrow with `pa.table(...)`, a zero-copy hand-off, before writing it to a new Parquet file.",
     "",
     "**Expected result:** a `portland-2017.parquet` file written locally; `table.num_rows` is 5."
    ]