Add forgotten translatable string in pg_checksums.c

Oversight in commit 280e5f14.

Author: Kyotaro Horiguchi
Discussion: https://postgr.es/m/20190606.200612.110313249.horikyota.ntt@gmail.com

src/bin/pg_checksums/pg_checksums.c

@@ -146,7 +146,7 @@ progress_report(bool force)
 	snprintf(current_size_str, sizeof(current_size_str), INT64_FORMAT,
 			 current_size / (1024 * 1024));
 
-	fprintf(stderr, "%*s/%s MB (%d%%) computed",
+	fprintf(stderr, _("%*s/%s MB (%d%%) computed"),
 			(int) strlen(current_size_str), current_size_str, total_size_str,
 			percent);