PYTHON-3445 Fix documentation for with_options (#1075)

Author: juliusgeo

pymongo/database.py

@@ -161,7 +161,7 @@ def with_options(
 
           >>> db1.read_preference
           Primary()
-          >>> from pymongo import ReadPreference
+          >>> from pymongo.read_preferences import Secondary
           >>> db2 = db1.with_options(read_preference=Secondary([{'node': 'analytics'}]))
           >>> db1.read_preference
           Primary()