Reformat all code to use shell instead of sh

snippets/merge-branch.md

@@ -8,12 +8,12 @@ Merges a branch into the current branch.
 - Use `git checkout <target-branch>` to switch to the branch into which you want to merge.
 - Use `git merge <source-branch>` to merge a branch into the current branch.
 
-```sh
+```shell
 git checkout <target-branch>
 git merge <source-branch>
 ```
 
-```sh
+```shell
 git checkout master
 git merge patch-1 # Merges the `patch-1` branch into `master`
 ```