[Compass-ci] Re: [PATCH compass-ci] doc: optimize os_mount.md

Usage example:

• • submit iperf.yaml testbox=vm-2p8g os_mount=nfs
• • submit iperf.yaml testbox=vm-2p8g os_mount=cifs
• • submit iperf.yaml testbox=vm-2p8g os_mount=initramfs
• • submit iperf.yaml testbox=dc-8g os_mount=container
• • submit iperf.yaml testbox=vm-2p8g os_mount=local

• • submit -m -c borrow-1h.yaml testbox=vm-2p8g os_mount=nfs
• • submit -m -c borrow-1h.yaml testbox=vm-2p8g os_mount=cifs
• • submit -m -c borrow-1h.yaml testbox=vm-2p16g os_mount=initramfs
• • submit -m -c borrow-1h.yaml testbox=dc-8g os_mount=container
• • submit -m -c borrow-1h.yaml testbox=taishan200-2280-2s48p-256g os_mount=local

简单缩进更好：

submit -m -c borrow-1h.yaml testbox=vm-2p8g os_mount=nfs submit -m -c borrow-1h.yaml testbox=vm-2p8g os_mount=cifs submit -m -c borrow-1h.yaml testbox=vm-2p16g os_mount=initramfs submit -m -c borrow-1h.yaml testbox=dc-8g os_mount=container submit -m -c borrow-1h.yaml testbox=taishan200-2280-2s48p-256g os_mount=local

以代码形式呈现，且方便拷贝粘帖。

Thanks, Fengguang