Bump assets/themes/onehalf from `3aa42a3` to `8992311`

Bumps [assets/themes/onehalf](https://github.com/sonph/onehalf) from `3aa42a3` to `8992311`.
- [Release notes](https://github.com/sonph/onehalf/releases)
- [Commits](3aa42a39ed...89923117bc)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

assets/themes/onehalf

@@ -1 +1 @@
-Subproject commit 3aa42a39ed3cddde0c53976a700b81b8a7067890
+Subproject commit 89923117bc49dd1e0c6b7fdd34bc6dc4d425fe1f