conf: default to $EDITOR/$GEDITOR

[oliver-sanders]

From the platforms proposal document: https://cylc.github.io/cylc-admin/proposal-config-changes.html#editors

Requirements check-list

• I have read CONTRIBUTING.md and added my name as a Code Contributor.
• Contains logically grouped changes (else tidy your branch by rebase).
• Does not contain off-topic changes (use other PRs for other changes).
• Appropriate tests are included (unit and/or functional).
• Appropriate change log entry included.
• No documentation update required (docs auto-generated from the config).

[datamel]

I have run the tests and checked the code. Happy with this change. As an aside (which became apparent through running your new test @oliver-sanders), the test battery is picking up the flow.rc and not using flow-tests.rc, is this the plan to get rid of flow-tests.rc? Apologies if I have missed something documented about this already!

[oliver-sanders]

the test battery is picking up the flow.rc and not using flow-tests.rc, is this the plan to get rid of flow-tests.rc? Apologies if I have missed something documented about this already!

Damn! That needs to be fixed. There is no plan to retire the flow-tests.rc though it will get renamed inline with the configuration file changes.

Please raise a bug report and tag it against 8.0a3.