Update fmt.mdx (#31553)
Update fmt.mdx (#31553)

* Update fmt.mdx

Fix insufficient explanation of "-check" option.

* Apply suggestions from code review

Co-authored-by: kmoe <589c6e96bba3acfb2818cd8391eda98c19b67d6a@users.noreply.github.com>

Co-authored-by: kmoe <589c6e96bba3acfb2818cd8391eda98c19b67d6a@users.noreply.github.com>
hashicorp/terraform,hashicorp/terraform,hashicorp/terraform