doc: update mailmap and AUTHORS

Based on their GitHub and other social media profiles as well as the
most recent of their authored commits, I suspect watson goes by "Thomas
Watson" and not the name currently listed in the .mailmap and AUTHORS
files. Update.

I'm doing this because it  helps avoid false positives in
`find-inactive-collaborators.mjs` which uses `git shortlog` which uses
`.mailmap`.

PR-URL: #39393
Reviewed-By: Michael Dawson <[email protected]>
Reviewed-By: James M Snell <[email protected]>

Author: Trott

.mailmap

@@ -393,7 +393,7 @@ Surya Panikkal <[email protected]> suryagh <[email protected]>
 Taehee Kang <[email protected]> hugnosis <[email protected]>
 Tanuja-Sawant <[email protected]> <[email protected]>
 Taylor Woll <[email protected]> taylor.woll <[email protected]>
-Thomas Watson Steen <[email protected]> Thomas Watson <[email protected]>
+Thomas Watson <[email protected]>
 Timothy O. Peters <[email protected]>
 Timur Shemsedinov <[email protected]> tshemsedinov <[email protected]>
 Ting Shao <[email protected]>

AUTHORS

@@ -1168,7 +1168,7 @@ Yoshiya Hinosawa <[email protected]>
 Syuhei Kobayashi <[email protected]>
 YutamaKotaro <[email protected]>
 MURAKAMI Masahiko <[email protected]>
-Thomas Watson Steen <[email protected]>
+Thomas Watson <[email protected]>
 Daijiro Yamada <[email protected]>
 Kelvin Jin <[email protected]>
 Mitsuo Utano <[email protected]>