gtkhtml3 soname bump in Rawhide

[Milan Crha]

	Hi,
just finished gtkhtml3 update to 3.91.4 has a soname bump, due
to changes in its API as was discovered in [1]. It has it since 3.91.3
release, somehow, only the soname wasn't changed.

I know this is kinda late notice, but the bug was discovered just before
the release.

I'm sorry for any inconvenience caused by this.
	Bye,
	Milan Crha

[1] https://bugzilla.redhat.com/show_bug.cgi?id=664279