[skip ci] Add instructions to finish the backport

Author: geo-ghci-int[bot]

BACKPORT_TODO

@@ -0,0 +1,20 @@
+Backport of #12829 to master
+
+Error on cherry-picking: 277912d080492f03a7f4d58a5889f3043050edb4
+
+To continue do:
+```bash
+git fetch && \
+  git checkout ghci/backport/12829-to-master && \
+  git reset --hard HEAD^ && \
+  git cherry-pick 277912d080492f03a7f4d58a5889f3043050edb4
+```
+Resolve the conflict, then:
+```bash
+git add <file> && \
+  git cherry-pick --continue
+```
+When all the conflicts are resolved, push the branch:
+```bash
+git push origin ghci/backport/12829-to-master --force
+```