[bug#65479] [PATCH core-updates 04/61] gnu: docbook-xsl: Add compatibility entry.

[Bruno Victal]

It turns out that we have been inserting incorrect entries in the XML
catalog for docbook-xsl.

The URIs 'http://docbook.sourceforge.net/release/xsl/current/' and 
'http://cdn.docbook.org/release/xsl/current/' are NOT interchangeable [1]
since the docbook-xsl package only provides the namespaced version.

I will prepare a v2 to fix this inaccuracy by adding a docbook-xsl-nons
package and rectify the catalog entries in both packages.


[1]: 
<https://github.com/docbook/xslt10-stylesheets/issues/201#issuecomment-741549069>

-- 
Furthermore, I consider that nonfree software must be eradicated.

Cheers,
Bruno.