`bin/shutdown.sh`'s output separates into multi-lines when existing more than one `pid`

[Alioth4J]

Describe the bug
If there are more than one pids, when executing bin/shutdown.sh, the output will be separated to multi-lines.

Expected behavior

$ sh bin/shutdown.sh
The nacosServer(39511 40444) is running...
Send shutdown request to nacosServer(39511 40444) OK

Actually behavior

$ sh bin/shutdown.sh
The nacosServer(39511
40444) is running...
Send shutdown request to nacosServer(39511
40444) OK

How to Reproduce
Steps to reproduce the behavior:

1. Start two nacos server instance.
2. Run bin/shutdown.sh.
3. See the output.

Desktop (please complete the following information):

• OS: Fedora
• Version nacos-server 3.0.2
• Module bin

Additional context
The problem is caused by pgrep, which puts one pid in one new line. I think we can add | xargs after pgrep -f nacos.nacos to format the output.

This does not have functional issues.