nx-X11/programs/Xserver/hw/nxagent/man/nxagent.1: Fix groff error rep… #204

Job	Run time
Build on ubuntu:16.04 - gcc	37s
Build on ubuntu:16.04 - clang	55s
Build on ubuntu:20.04 - gcc	8m 17s
Build on ubuntu:20.04 - clang	8m 25s
Build on ubuntu:22.04 - gcc	8m 6s
Build on ubuntu:22.04 - clang	7m 59s
Build on debian:stable - gcc	8m 34s
Build on debian:stable - clang	8m 33s
Build on debian:sid - gcc	7m 53s
Build on debian:sid - clang	8m 37s
Build on quay.io/centos/centos:7 - gcc	6s
Build on quay.io/centos/centos:7 - clang	7s
Build on quay.io/centos/centos:stream9 - gcc	8m 41s
Build on quay.io/centos/centos:stream9 - clang	9m 49s
Build on fedora:latest - gcc	9m 19s
Build on fedora:latest - clang	1h 38m 45s
	3h 14m 43s

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