meta: consolidate email addresses for MarshallOfSound

PR-URL: #39651
Reviewed-By: James M Snell <jasnell@gmail.com>

.mailmap

@@ -350,6 +350,7 @@ Sam P Gallagher-Bishop <samgallagherb@gmail.com> <SPGB@users.noreply.github.com>
 Sam Roberts <vieuxtech@gmail.com> <sam@strongloop.com>
 Sam Shull <brickysam26@gmail.com> <brickysam26@samuel-shulls-computer.local>
 Sam Shull <brickysam26@gmail.com> <sshull@squaremouth.com>
+Samuel Attard <samuel.r.attard@gmail.com> <sattard@slack-corp.com>
 Samantha Sample <ssample812@gmail.com> <=>
 Sambasiva Suda <sambasivarao@gmail.com>
 San-Tai Hsu <v@fatpipi.com>

AUTHORS

@@ -2791,7 +2791,6 @@ Mike MacCana <mike.maccana@gmail.com>
 Tim Baverstock <tim.baverstock@corp.badoo.com>
 Walle Cyril <cyril.walle@protonmail.com>
 Xu Meng <dmabupt@gmail.com>
-Samuel Attard <sattard@slack-corp.com>
 Ben L. Titzer <titzer@google.com>
 Ojasvi Monga <ojasvi@Ojasvis-MacBook-Air.local>
 Shajan Jacob <shajanjp@gmail.com>