gnucash-docs stable: Use https to load docbookx.dtd.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash-docs/commit/285f67b7 (commit)
	from  https://github.com/Gnucash/gnucash-docs/commit/40cc42d7 (commit)



commit 285f67b749fd81013d3037bde42621baa40681be
Author: John Ralls <jralls at ceridwen.us>
Date:   Thu Oct 9 17:00:17 2025 -0700

    Use https to load docbookx.dtd.
    
    Fixes build failures on code's Win32 VM. It seemed not to be a problem anywhere else, but it
    should be harmless.



Summary of changes:
 docbook/gnc-docbookx.dtd | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)