[GNC] Guile warning

[David Carlson]

I am using Gnucash 5.13 or possibly 5.11 but it is labelled 5.13 in flatpak
on Ubuntu Linux.  After it has run for a while, the warning "Some
deprecated features have been used.  Set the environment
variable GUILE_WARN_DEPRECATED to "detailed" and rerun the
program to get more information.  Set it to "no" to suppress
this message." appears in the terminal.

I won't be able to follow up for a few days so I am posting here in case
others may benefit from this.

-- 
David Carlson