documentation, similar to "make doc".
(merge ff4ec8ded0 ps/meson-build-docs later to maint).
+ * Dip our toes a bit to (optionally) use Rust implemented helper
+ called from our C code.
+
Fixes since v2.51
-----------------
checking has been updated to use the existing helper function.
(merge ecc5749578 js/curl-off-t-fixes later to maint).
+ * "git reflog write" did not honor the configured user.name/email
+ which has been corrected.
+
+ * Handling of an empty subdirectory of .git/refs/ in the ref-files
+ backend has been corrected.
+
* Other code cleanup, docfix, build fix, etc.
(merge 823d537fa7 kh/doc-git-log-markup-fix later to maint).
(merge cf7efa4f33 rj/t6137-cygwin-fix later to maint).
(merge fafc9b08b8 ag/doc-sendmail-gmail-example-update later to maint).
(merge a66fc22bf9 rs/get-oid-with-flags-cleanup later to maint).
(merge e1d062e8ba ps/odb-clean-stale-wrappers later to maint).
+ (merge fdd21ba116 mh/doc-credential-url-prefix later to maint).