Better user experience when editing rules of different types

[jonathonherbert]

What does this change?

A few tweaks when editing rules of different types:

• the rule type is now respected, changing when the rule data changes
• the input changes from a text to textarea when editing XML rules, to reflect their multiline content

I've also moved the radio buttons nearer the pattern input, as the two fields are very related – one affects the other's presentation.

How to test

Have a play inspecting and editing rules of different types. Do the changes make sense?

[rhystmills]

I think this also include some changes from: https://github.com/guardian/typerighter/pull/354/files

Going to try rebasing on: https://github.com/guardian/typerighter/pull/354/files

Have removed the last three commits and pushed again.