Improve I18N Issues (Based on 1.2.5)

Don’t split full sentences into several parts; this will do bad translations.

As the above, I made some modifications.

wp-downgrade.php, line 110

<td><?php printf(__('Exact version number from <a href="%s" target="_blank">WP Releases</a> for example "4.9.8". Leave empty to disable.', 'wp-downgrade'),$release_link,); ?></td>

wp-downgrade.php, line 134

<td> <span id="download-url-text" style="display:<?php if (get_option('wpdg_edit_download_url')){ echo 'inline';} else {echo 'none';} ?>"><?php printf(__('Usually you <strong>do not</strong> need to change this. But you can, if necessary. Must be a valid URL to a WordPress ZIP. <strong>Be careful!</strong> The content will not be verified! WordPress will use what ever you give here, even if it does not contain release %s or for example a wrong language. After your special update is done, you need to check for success yourself. And after that, you should turn off this option.', 'wp-downgrade'),get_option('wpdg_specific_version_name')); ?></span></td>

wp-downgrade.php, line 149

<?php printf(__('<strong>All fine!</strong> You are currently on your desired release. And it will stay like that. <br>If you ever want to <strong>reinstall</strong> %1$s, you have to switch to another version and come back. If you want to return to the regular update channel, you need to empty the version number above and go to <a href="%2$s">Update Core</a>.', 'wp-downgrade'),get_option('wpdg_specific_version_name'),get_admin_url( null, '/update-core.php' )); ?>

wp-downgrade.php, line 153

<p><strong><?php printf(__('In order to perform the upgrade/downgrade to WP %1$s please go to <a href="%2$s">Update Core</a>.', 'wp-downgrade'),get_option('wpdg_specific_version_name'),get_admin_url( null, '/update-core.php' )); ?></strong></p>

I also make UI string “Settings” translatable.

wp-downgrade.php, line 57

$links[] = '<a href="'. esc_url( get_admin_url(null, 'options-general.php?page=wpdowngrade') ) .'">' . __( 'Settings', 'wp-downgrade' ) . '</a>';