Etc/UCT is now an alias for Etc/UTC

(Problem reported by Isiah Meadows.)
* NEWS: Document the change.
* backward (Etc/UCT): New backward-compatibility link.
(UCT): Now links to Etc/UTC, not Etc/UCT.
* etcetera (Etc/UCT): Remove.

NEWS

@@ -17,6 +17,13 @@ Unreleased, experimental changes
     Israel observed DST in 1980 (08-02/09-13) and 1984 (05-05/08-25).
     (Thanks to Alois Treindl and Isaac Starkman.)
 
+  Changes to time zone abbreviations
+
+    Etc/UCT is now a backward-compatibility link to Etc/UTC, instead
+    of being a separate zone that generates the abbreviation "UCT",
+    which nowadays is typically a typo.  (Problem reported by Isiah
+    Meadows.)
+
   Changes to documentation
 
     Mention Internet RFC 8536 (February 2019), which documents TZif.

backward

@@ -77,6 +77,7 @@ Link	Pacific/Easter		Chile/EasterIsland
 Link	America/Havana		Cuba
 Link	Africa/Cairo		Egypt
 Link	Europe/Dublin		Eire
+Link	Etc/UTC			Etc/UCT
 Link	Europe/London		Europe/Belfast
 Link	Europe/Chisinau		Europe/Tiraspol
 Link	Europe/London		GB
@@ -111,7 +112,7 @@ Link	Asia/Taipei		ROC
 Link	Asia/Seoul		ROK
 Link	Asia/Singapore		Singapore
 Link	Europe/Istanbul		Turkey
-Link	Etc/UCT			UCT
+Link	Etc/UTC			UCT
 Link	America/Anchorage	US/Alaska
 Link	America/Adak		US/Aleutian
 Link	America/Phoenix		US/Arizona

etcetera

@@ -19,7 +19,6 @@
 
 Zone	Etc/GMT		0	-	GMT
 Zone	Etc/UTC		0	-	UTC
-Zone	Etc/UCT		0	-	UCT
 
 # The following link uses older naming conventions,
 # but it belongs here, not in the file 'backward',