Merge pull request #39 from MattF-NSIDC/fix-docs-typo

Fix typo (`wtalchemy`) in docs example code

wtforms_sqlalchemy/orm.py

@@ -297,7 +297,7 @@ def model_form(
     """
     Create a wtforms Form for a given SQLAlchemy model class::
 
-        from wtalchemy.orm import model_form
+        from wtforms_sqlalchemy.orm import model_form
         from myapp.models import User
         UserForm = model_form(User)