Add a release note (feature)

The `git backfill` command has been accepted into upstream Git; Its
`--batch-size=<n>` option has been renamed to `--min-batch-size=<n>`,
though.

Signed-off-by: gitforwindowshelper[bot] <[email protected]>

Author: gitforwindowshelper[bot]

ReleaseNotes.md

@@ -50,6 +50,7 @@ Git for Windows v2.48.1 was the last version to ship with the i686 ("32-bit") va
 * Comes with [OpenSSH v9.9.P2](https://github.com/openssh/openssh-portable/releases/tag/V_9_9_P2).
 * Comes with [PCRE2 v10.45](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.45).
 * The previously-experimental `--full-name-hash` option has been accepted into upstream Git as `--name-hash-version=2` and is no longer experimental.
+* The `git backfill` command has been accepted into upstream Git; Its `--batch-size=<n>` option has been renamed to `--min-batch-size=<n>`, though.
 
 ### Bug Fixes