Message style fix

from Euler Taveira

src/backend/commands/copy.c

@@ -874,7 +874,7 @@ DoCopy(const CopyStmt *stmt, const char *queryString, uint64 *processed)
 			if (is_from)
 				ereport(ERROR,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				  errmsg("COPY FROM not supported with row-level security."),
+				  errmsg("COPY FROM not supported with row-level security"),
 						 errhint("Use INSERT statements instead.")));
 
 			/* Build target list */

src/test/regress/expected/rowsecurity.out

@@ -2674,7 +2674,7 @@ COPY copy_t FROM STDIN; --fail - insufficient privilege to bypass rls.
 ERROR:  insufficient privilege to bypass row-level security
 SET row_security TO ON;
 COPY copy_t FROM STDIN; --fail - COPY FROM not supported by RLS.
-ERROR:  COPY FROM not supported with row-level security.
+ERROR:  COPY FROM not supported with row-level security
 HINT:  Use INSERT statements instead.
 -- Check COPY FROM as user with permissions and BYPASSRLS
 SET SESSION AUTHORIZATION rls_regress_exempt_user;