Reformat all code to use shell instead of sh

snippets/create-fixup-commit.md

@@ -8,11 +8,11 @@ Creates a fixup commit that can be autosquashed in the next rebase.
 - Use `git commit --fixup <commit>` to create a fixup commit for the specified `<commit>`.
 - After running `git rebase --autosquash`, fixup commits will be automatically squashed into the commits they reference.
 
-```sh
+```shell
 git commit --fixup <commit>
 ```
 
-```sh
+```shell
 git add .
 git commit --fixup 3050fc0de
 # Created a fixup commit for `3050fc0de`