Update doc/io.rst

Co-authored-by: Mathias Hauser <[email protected]>

Author: dcherian

doc/io.rst

@@ -106,7 +106,7 @@ you try to perform some sort of actual computation. For an example of how these
 lazy arrays work, see the OPeNDAP section below.
 
 There may be minor differences in the :py:class:`Dataset` object returned
-when reading a NetCDF file with different engines.  For example,
+when reading a NetCDF file with different engines. For example,
 single-valued attributes are returned as scalars by the default
 ``engine=netcdf4``, but as arrays of size ``(1,)`` when reading with
 ``engine=h5netcdf``.