DOC: Clearer coordinate docstring for open_rasterio (#811)

* docs(_io.py): clearer docstring

see #805
for discussion

* docs(_io.py): add back "automatically"

* style(_io.py): trim whitespace

rioxarray/_io.py

@@ -1016,10 +1016,7 @@ def open_rasterio(
 
     This should work with any file that rasterio can open (most often:
     geoTIFF). The x and y coordinates are generated automatically from the
-    file's geoinformation, shifted to the center of each pixel (see
-    `"PixelIsArea" Raster Space
-    <http://web.archive.org/web/20160326194152/http://remotesensing.org/geotiff/spec/geotiff2.5.html#2.5.2>`_
-    for more information).
+    file's geoinformation and refer to the center of the pixel.
 
     .. versionadded:: 0.13 band_as_variable