Properly increase the index counter.

NEWS.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 For changes prior to version 6.0.0, please see [`NEWS.old`](news.old).
 
+## Unreleased
+
+### Fixed
+
+- Fixed a regression concerning `linktitles-cli` progress display that was
+  introduced in v8.0.0.
+  
 ## [8.0.0][] - 2021-04-06
 
 ### Changed

linktitles-cli.php

@@ -177,6 +177,7 @@ class Cli extends \Maintenance {
 		foreach ( $res as $row ) {
 			$title = \Title::makeTitleSafe( $row->page_namespace, $row->page_title );
 			$numProcessed += 1;
+			$index += 1;
 			$this->output( sprintf( "\rPage #%d (%02.0f%%) ", $index, $numProcessed / $numPages * 100 ) );
 			Extension::processPage( $title, $context );
 		}