gnucash master: I18N: Fix typo Exsiting -> Existing

[Frank H.Ellenberger]

Updated	 via  https://github.com/Gnucash/gnucash/commit/1467f332 (commit)
	from  https://github.com/Gnucash/gnucash/commit/54859eaf (commit)



commit 1467f332757bc971cc70f2e1dc30fa6b8138022e
Author: Yuri Chornoivan <yurchor at ukr.net>
Date:   Tue Jun 2 13:00:37 2020 +0300

    I18N: Fix typo Exsiting -> Existing



Summary of changes:
 gnucash/gnome-utils/dialog-assoc-utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)