pppd.8: Fix groff warning (#547) #683

Job	Run time
Buildroot (qemu_x86_defconfig, glibc)	1m 59s
Buildroot (qemu_x86_defconfig, uclibc)	1m 56s
Buildroot (qemu_x86_defconfig, musl)	2m 1s
Buildroot (qemu_x86_64_defconfig, glibc)	1m 59s
Buildroot (qemu_x86_64_defconfig, uclibc)	1m 56s
Buildroot (qemu_x86_64_defconfig, musl)	1m 54s
Buildroot (raspberrypi4_defconfig, glibc)	2m 6s
Buildroot (raspberrypi4_defconfig, uclibc)	2m 42s
Buildroot (raspberrypi4_defconfig, musl)	2m 40s
Buildroot (raspberrypi4_64_defconfig, glibc)	1m 59s
Buildroot (raspberrypi4_64_defconfig, uclibc)	2m 45s
Buildroot (raspberrypi4_64_defconfig, musl)	1m 57s
Buildroot (qemu_ppc64le_pseries_defconfig, glibc)	2m 53s
Buildroot (qemu_ppc64le_pseries_defconfig, uclibc)	2m 8s
Buildroot (qemu_ppc64le_pseries_defconfig, musl)	2m 5s
Buildroot (qemu_mips32r2_malta_defconfig, glibc)	2m 15s
Buildroot (qemu_mips32r2_malta_defconfig, uclibc)	2m 38s
Buildroot (qemu_mips32r2_malta_defconfig, musl)	2m 12s
Buildroot (qemu_mips64_malta_defconfig, glibc)	2m 44s
Buildroot (qemu_mips64_malta_defconfig, uclibc)	1m 54s
Buildroot (qemu_mips64_malta_defconfig, musl)	1m 52s
Buildroot (qemu_riscv32_virt_defconfig, glibc)	2m 16s
Buildroot (qemu_riscv32_virt_defconfig, uclibc)	1m 56s
Buildroot (qemu_riscv32_virt_defconfig, musl)	2m 9s
Buildroot (qemu_riscv64_virt_defconfig, glibc)	1m 58s
Buildroot (qemu_riscv64_virt_defconfig, uclibc)	2m 36s
Buildroot (qemu_riscv64_virt_defconfig, musl)	2m 36s
	1h 0m 6s

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