Apply style guide to placeholders in "Syncing a fork" (#32313)

Co-authored-by: Alex Nguyen <[email protected]>

Author: hsnabszhdn

content/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork.md

@@ -42,10 +42,10 @@ If the changes from the upstream repository cause conflicts, {% data variables.p
 
 {% data reusables.cli.about-cli %} To learn more about {% data variables.product.prodname_cli %}, see "[AUTOTITLE](/github-cli/github-cli/about-github-cli)."
 
-To update the remote fork from its parent, use the `gh repo sync -b BRANCHNAME` subcommand and supply your fork and branch name as arguments.
+To update the remote fork from its parent, use the `gh repo sync -b BRANCH-NAME` subcommand and supply your fork and branch name as arguments.
 
 ```shell
-gh repo sync owner/cli-fork -b BRANCH_NAME
+gh repo sync owner/cli-fork -b BRANCH-NAME
 ```
 
 If the changes from the upstream repository cause conflict then the {% data variables.product.prodname_cli %} can't sync. You can set the `--force` flag to overwrite the destination branch.
@@ -56,15 +56,15 @@ Before you can sync your fork with an upstream repository, you must configure a
 
 {% data reusables.command_line.open_the_multi_os_terminal %}
 1. Change the current working directory to your local project.
-1. Fetch the branches and their respective commits from the upstream repository. Commits to `BRANCHNAME` will be stored in the local branch `upstream/BRANCHNAME`.
+1. Fetch the branches and their respective commits from the upstream repository. Commits to `BRANCH-NAME` will be stored in the local branch `upstream/BRANCH-NAME`.
 
    ```shell
    $ git fetch upstream
    > remote: Counting objects: 75, done.
    > remote: Compressing objects: 100% (53/53), done.
    > remote: Total 62 (delta 27), reused 44 (delta 9)
    > Unpacking objects: 100% (62/62), done.
-   > From https://{% data variables.command_line.codeblock %}/ORIGINAL_OWNER/ORIGINAL_REPOSITORY
+   > From https://{% data variables.command_line.codeblock %}/ORIGINAL-OWNER/ORIGINAL-REPOSITORY
    >  * [new branch]      main     -> upstream/main
    ```