(maint) improve manpage

This improves the facter manpage to fix parsing errors due to the
missing short description in the NAME section, makes the formatting
consistent with most other manpages, and updates the DESCRIPTION section
using the one in the project's README, which is more useful this context.

Author: jcharaoui

man/man8/facter.8

@@ -4,13 +4,13 @@
 .TH "FACTER" "8" "July 2021" "Puppet, Inc." "Facter manual"
 .
 .SH "NAME"
-\fBfacter\fR
+facter \- collect and display facts about the current system
 .
 .SH "SYNOPSIS"
-facter [options] [query] [query] [\.\.\.]
+\fBfacter\fR [options] [query] [query] [\.\.\.]
 .
 .SH "DESCRIPTION"
-Collect and display facts about the current system\. The library behind Facter is easy to extend, making Facter an easy way to collect information about a system\.
+\fBfacter\fR is a command-line tool that gathers basic facts about nodes (systems) such as hardware details, network settings, OS type and version, and more\. These facts are made available as variables in your Puppet manifests and can be used to inform conditional expressions in Puppet\.
 .
 .P
 If no queries are given, then all facts will be returned\.