Apply suggestion from @mroeschke

Author: mroeschke

doc/source/user_guide/io.rst

@@ -173,7 +173,7 @@ dtype_backend : {"numpy_nullable", "pyarrow"}, defaults to NumPy backed DataFram
 engine : {``'c'``, ``'python'``, ``'pyarrow'``}
   Parser engine to use. The C and pyarrow engines are faster, while the python engine
   is currently more feature-complete. Multithreading is currently only supported by
-  the pyarrow engine. Some features of "pyarrow" engine
+  the pyarrow engine. Some features of the "pyarrow" engine
   are unsupported or may not work correctly.
 converters : dict, default ``None``
   Dict of functions for converting values in certain columns. Keys can either be