gnucash maint: [report-core] disallow define-report with incomplete export info

[Christopher Lam]

Updated	 via  https://github.com/Gnucash/gnucash/commit/85a4baeb (commit)
	from  https://github.com/Gnucash/gnucash/commit/45cb454b (commit)



commit 85a4baeb21a1b7e1d9158d3a202d69c3c4844c12
Author: Christopher Lam <christopher.lck at gmail.com>
Date:   Wed May 5 08:52:08 2021 +0800

    [report-core] disallow define-report with incomplete export info
    
    if exporting is allowed, 'export-types and 'export-thunk must both be
    defined.



Summary of changes:
 gnucash/report/report-core.scm      | 10 +++++++---
 gnucash/report/test/test-report.scm | 16 ++++++++++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)