gnucash maint: Improve invoice import column headers

[Frank H.Ellenberger]

Updated	 via  https://github.com/Gnucash/gnucash/commit/24094222 (commit)
	from  https://github.com/Gnucash/gnucash/commit/adae341d (commit)



commit 24094222d1e9947f1f65e9d84083f52f5a13bd57
Author: Frank H. Ellenberger <frank.h.ellenberger at gmail.com>
Date:   Wed Aug 14 11:33:37 2019 +0200

    Improve invoice import column headers
    
    Use underline only for mnemonics.
    Capitalize column headers.
    
    Try to reduce number of translatable strings - still incomplete.
    
    Follow up of commit aadb3d1.



Summary of changes:
 .../import-export/bi-import/dialog-bi-import-gui.c | 48 +++++++++++-----------
 1 file changed, 24 insertions(+), 24 deletions(-)