Use unversioned docdir.
--- doc/Makefile.in.orig	2020-07-04 01:20:16.000000000 -0500
+++ doc/Makefile.in	2023-09-25 19:52:30.000000000 -0500
@@ -320,7 +320,7 @@
 builddir = @builddir@
 datadir = @datadir@
 datarootdir = @datarootdir@
-docdir = $(datadir)/doc/$(PACKAGE)-$(VERSION)
+docdir = $(datadir)/doc/$(PACKAGE)
 dvidir = @dvidir@
 exec_prefix = @exec_prefix@
 host = @host@
--- doc/libvorbis/Makefile.in.orig	2020-07-04 01:20:16.000000000 -0500
+++ doc/libvorbis/Makefile.in	2023-09-25 19:52:30.000000000 -0500
@@ -260,7 +260,7 @@
 builddir = @builddir@
 datadir = @datadir@
 datarootdir = @datarootdir@
-docdir = $(datadir)/doc/$(PACKAGE)-$(VERSION)/libvorbis
+docdir = $(datadir)/doc/$(PACKAGE)/libvorbis
 dvidir = @dvidir@
 exec_prefix = @exec_prefix@
 host = @host@
--- doc/vorbisenc/Makefile.in.orig	2020-07-04 01:20:16.000000000 -0500
+++ doc/vorbisenc/Makefile.in	2023-09-25 19:52:30.000000000 -0500
@@ -260,7 +260,7 @@
 builddir = @builddir@
 datadir = @datadir@
 datarootdir = @datarootdir@
-docdir = $(datadir)/doc/$(PACKAGE)-$(VERSION)/vorbisenc
+docdir = $(datadir)/doc/$(PACKAGE)/vorbisenc
 dvidir = @dvidir@
 exec_prefix = @exec_prefix@
 host = @host@
--- doc/vorbisfile/Makefile.in.orig	2020-07-04 01:20:16.000000000 -0500
+++ doc/vorbisfile/Makefile.in	2023-09-25 19:52:30.000000000 -0500
@@ -260,7 +260,7 @@
 builddir = @builddir@
 datadir = @datadir@
 datarootdir = @datarootdir@
-docdir = $(datadir)/doc/$(PACKAGE)-$(VERSION)/vorbisfile
+docdir = $(datadir)/doc/$(PACKAGE)/vorbisfile
 dvidir = @dvidir@
 exec_prefix = @exec_prefix@
 host = @host@