A Few Problems with Pyface Docs

On the Overview page in the Actions section, there is a syntax error

- [x] in docs/source/overview.rst line 232
```
try:
self._editor.save()
except IOError, e:
```

- [ ] Also more generally, in the other docs, such as for Traits and TraitsUI, there are more self-contained examples that can be run, and in many cases their results are shown in the docs. I found this helpful for my understanding. In the Pyface docs. however, I found it more difficult to actually run the example code given for myself to fully understand what it was doing.

- [x] in docs/source/toolkits.rst line 50
Typo on Toolkits page "This is a callable object which expects to be given **the an** identifier"

- [x] In example code for GUIApplication Example, there is a return statement that isn't indented:
in docs/source/applications.rst line 202

```
def create_python_shell_window(application, **kwargs):
window = PythonShellWindow()
window.menu_bar_manager = MenuBarManager(
MenuManager(
Group(CreateWindowAction(application=application)),
Group(
CloseWindowAction(window=window),
ExitAction(application=application),
),
name='&File',
),
MenuManager(
AboutAction(application=application),
name='&Help',
)
)
return window
```