Add tab completion for REJECT_LIMIT option.

This addresses an oversight in commit 4ac2a9bec, which introduced the
REJECT_LIMIT option to the COPY command.

Author: Atsushi Torikoshi <torikoshia@oss.nttdata.com>
Reviewed-by: Yugo Nagata <nagata@sraoss.co.jp>
Discussion: https://postgr.es/m/ac23e824d1d602f113a89c91ee56fb23@oss.nttdata.com

src/bin/psql/tab-complete.in.c

@@ -3289,7 +3289,7 @@ match_previous_words(int pattern_id,
 		COMPLETE_WITH("FORMAT", "FREEZE", "DELIMITER", "NULL",
 					  "HEADER", "QUOTE", "ESCAPE", "FORCE_QUOTE",
 					  "FORCE_NOT_NULL", "FORCE_NULL", "ENCODING", "DEFAULT",
-					  "ON_ERROR", "LOG_VERBOSITY");
+					  "ON_ERROR", "LOG_VERBOSITY", "REJECT_LIMIT");
 
 	/* Complete COPY <sth> FROM|TO filename WITH (FORMAT */
 	else if (Matches("COPY|\\copy", MatchAny, "FROM|TO", MatchAny, "WITH", "(", "FORMAT"))