Undo (saved) edits to the specification file

[HumzahJavid]

Given a design of the front end in which the specification file can be viewed, edited and then saved.

This issue lists a user story which suggests the requirement of an undo feature.

As an end user I want to be able to undo changes I have made to the specification file since opening the admin portal. This is in case I have made a mistake (error, destructive overwrite) and clicked saved.