fix typos in doc

Author: benbovy

doc/api.rst

@@ -17,7 +17,7 @@ properties listed below. Proper use of this accessor should be like:
 .. code-block:: python
 
    >>> import xarray as xr   # first import xarray
-   >>> import xsimlab       # import xsimlab (the simlab xarray accessor is registered)
+   >>> import xsimlab       # import xsimlab (the 'xsimlab' accessor is registered)
    >>> ds = xr.Dataset()
    >>> ds.xsimlab.<meth_or_prop>   # access to the methods and properties listed below
 

doc/develop.rst

@@ -148,7 +148,7 @@ Every significative code contribution should be listed in the
 Contributing to documentation
 -----------------------------
 
-xarray uses Sphinx_ for documentation, hosted on http://readthedocs.org .
+xarray-simlab uses Sphinx_ for documentation, hosted on http://readthedocs.org .
 Documentation is maintained in the RestructuredText markup language (``.rst``
 files) in ``xarray-simlab/doc``.