Fix docs errors

1.Grammar error: 'return' should be 'returns'; 'would is' should be
'would be'.
2.Reloader is used to reload and fork process if modules were changed
rather than when an exception occurred.
3.The sample code is not concise enough.

docs/errorhandling.rst

@@ -76,9 +76,9 @@ Error handlers
 You might want to show custom error pages to the user when an error occurs.
 This can be done by registering error handlers.
 
-An error handler is a normal view function that return a response, but instead
+An error handler is a normal view function that returns a response, but instead
 of being registered for a route, it is registered for an exception or HTTP
-status code that would is raised while trying to handle a request.
+status code that would be raised while trying to handle a request.
 
 Registering
 ```````````
@@ -184,7 +184,7 @@ options in order to use your favorite debugger:
 
 * ``debug``        - whether to enable debug mode and catch exceptions
 * ``use_debugger`` - whether to use the internal Flask debugger
-* ``use_reloader`` - whether to reload and fork the process on exception
+* ``use_reloader`` - whether to reload and fork the process if modules were changed
 
 ``debug`` must be True (i.e., exceptions must be caught) in order for the other
 two options to have any value.
@@ -205,11 +205,6 @@ Then in your application's entry-point (main.py), you could have something like:
        # To allow aptana to receive errors, set use_debugger=False
        app = create_app(config="config.yaml")
 
-       if app.debug: use_debugger = True
+       use_debugger = app.debug and not(app.config.get('DEBUG_WITH_APTANA'))
-       try:
-           # Disable Flask's debugger if external debugger is requested
-           use_debugger = not(app.config.get('DEBUG_WITH_APTANA'))
-       except:
-           pass
        app.run(use_debugger=use_debugger, debug=app.debug,
                use_reloader=use_debugger, host='0.0.0.0')