clean useless whitespaces in filter-branch example (#1710)

Co-authored-by: hubwriter <[email protected]>

Author: maximd

content/github/using-git/splitting-a-subfolder-out-into-a-new-repository.md

@@ -36,7 +36,7 @@ If you create a new clone of the repository, you won't lose any of your Git hist
     {% endwindows %}
     - `BRANCH-NAME`: The default branch for your current project, for example, `main` or `gh-pages`.
     ```shell
-    $ git filter-branch --prune-empty --subdirectory-filter <em>FOLDER-NAME  BRANCH-NAME </em>
+    $ git filter-branch --prune-empty --subdirectory-filter <em>FOLDER-NAME BRANCH-NAME</em>
     # Filter the specified branch in your directory and remove empty commits
     > Rewrite 48dc599c80e20527ed902928085e7861e6b3cbe6 (89/89)
     > Ref 'refs/heads/<em>BRANCH-NAME</em>' was rewritten