chore(3p/sources): Bump channels & overlays

* //3p/sources: switch stable channel from 21.11 (!) to 23.05

* //users: adapt to emacsUnstable to emacs-unstable rename

* //users/grfn: use default Linux kernel version everywhere,
  as 5.15 has broken in this version of nixos-unstable.

* //3p/cgit: adapt to git 2.41.0

  The committed changes are the same as the [patch1] I've submitted
  to cgit-pink which is in turn based on Christian Hesse's [patch2].

patch1: https://causal.agency/list/thread/20230624144033.802270-1-sternenseemann%40systemli.org.html#20230624144033.802270-2-sternenseemann@systemli.org>
patch2: https://lists.zx2c4.com/pipermail/cgit/2023-June/004843.html

Co-authored-by: Christian Hesse <mail@eworm.de>

Change-Id: I549a62e7c85c66d772edda997819a40f2d5835d7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8855
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Reviewed-by: grfn <grfn@gws.fyi>

third_party/cgit/cgit.h

@@ -1,25 +1,33 @@
 #ifndef CGIT_H
 #define CGIT_H
 
-
-#include <git-compat-util.h>
 #include <stdbool.h>
 
+#include <git-compat-util.h>
+
+#include <archive.h>
 #include <cache.h>
-#include <grep.h>
-#include <object.h>
-#include <object-store.h>
-#include <tree.h>
 #include <commit.h>
-#include <tag.h>
-#include <diff.h>
 #include <diffcore.h>
-#include <strvec.h>
+#include <diff.h>
+#include <environment.h>
+#include <graph.h>
+#include <grep.h>
+#include <hex.h>
+#include <log-tree.h>
+#include <notes.h>
+#include <object.h>
+#include <object-name.h>
+#include <object-store.h>
 #include <refs.h>
 #include <revision.h>
-#include <log-tree.h>
-#include <archive.h>
+#include <setup.h>
 #include <string-list.h>
+#include <strvec.h>
+#include <tag.h>
+#include <tree.h>
+#include <utf8.h>
+#include <wrapper.h>
 #include <xdiff-interface.h>
 #include <xdiff/xdiff.h>
 #include <utf8.h>