- Moved backend determination to `config.el`
- Refactored function
- Replaced unnecessary backquote construct with simple quotation
- Replaced `pcase` form with only one-arm with `when` or `unless` form
This moves the point and content of the window close to where you were
before you ran perltidy. Of course if perltidy adds or removes a
significant amount of characters / lines as part of tidying, the point
will be moved by that amount. However in practice this I've found this
to be close enough.
