doc PG relnotes: add attribution for time zone data files items

This is needed for a future script to add commit links;  specifically we
need the closing parentheses of the attribution.

Backpatch-through: 12

doc/src/sgml/release-15.sgml

@@ -3711,7 +3711,7 @@ Branch: REL_12_STABLE [b59ae79b7] 2024-02-01 15:57:53 -0500
       release 2024a for DST law changes in Greenland, Kazakhstan, and
       Palestine, plus corrections for the Antarctic stations Casey and
       Vostok.  Also historical corrections for Vietnam, Toronto, and
-      Miquelon.
+      Miquelon. (Tom Lane)
      </para>
     </listitem>
 
@@ -7984,7 +7984,7 @@ Branch: REL_11_STABLE [7228f2f81] 2023-04-18 14:46:39 -0400
      <para>
       Update time zone data files to <application>tzdata</application>
       release 2023c for DST law changes in Egypt, Greenland, Morocco, and
-      Palestine.
+      Palestine. (Tom Lane)
      </para>
 
      <para>
@@ -9209,7 +9209,7 @@ Branch: REL_11_STABLE [7ddc428ef] 2023-01-31 17:37:34 -0500
       Update time zone data files to <application>tzdata</application>
       release 2022g for DST law changes in Greenland and Mexico,
       plus historical corrections for northern Canada, Colombia, and
-      Singapore.
+      Singapore. (Tom Lane)
      </para>
 
      <para>
@@ -9798,7 +9798,7 @@ Branch: REL_10_STABLE [b3326a753] 2022-11-01 17:09:21 -0400
       Update time zone data files to <application>tzdata</application>
       release 2022f for DST law changes in Chile, Fiji, Iran, Jordan,
       Mexico, Palestine, and Syria, plus historical corrections for Chile,
-      Crimea, Iran, and Mexico.
+      Crimea, Iran, and Mexico. (Tom Lane)
      </para>
 
      <para>