When syntax highlighting was disabled globally, we were deleting the

form field from the AccountSettingsForm. However, later on we were

trying to read from this field, causing an exception and the my account

page to not load.
Now when syntax highlighting is disabled, we mark the field as disabled

and refuse updates to it. It will also always render as if the user had

it disabled so it does not appear in a disabled but always on state for

the user.

Ran unit tests.
The my account page no longer raises an exception.