doc: fix manpage warning

LC_ALL=C.UTF-8 MANROFFSEQ='' MANWIDTH=80 man --warnings -E UTF-8 -l -Tutf8 -Z ./doc/node.1 > /dev/null
mdoc warning: Empty input line #389

PR-URL: #20383
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

doc/node.1

@@ -384,4 +384,3 @@ IRC (Node.js core development):
 .Sh AUTHORS
 Written and maintained by 1000+ contributors:
 .Sy https://github.com/nodejs/node/blob/master/AUTHORS
-.