Improve I18N Issues (Based on 1.0.0)

I found some I18N issues and I listed the modifications as the following.

admin\class-cf7-visited-pages-url-tracking-admin.php, Line 110

add_menu_page(__( 'CF7 - Track visited pages', 'cf7-visited-pages-url-tracking' ),__( 'CF7 - Track visited pages', 'cf7-visited-pages-url-tracking' ),'manage_options','cf7vput_settings_page',array($this,'cf7vput_settings_page_callback'),'dashicons-visibility');

admin\class-cf7-visited-pages-url-tracking-admin.php, Line 136

<p><?php _e('You need to add <code>[CF7VPUT_VISITED_Details]</code> into mail template of admin.','cf7-visited-pages-url-tracking'); ?> (<a href="<?php echo esc_url(plugin_dir_url( __FILE__ ) . 'images/how-to-use.png');?>" target="_blank"><?php esc_html_e( 'screenshot', 'cf7-visited-pages-url-tracking' ); ?></a>)</p>

admin\class-cf7-visited-pages-url-tracking-admin.php, Line 150

<p><?php _e('Users visit pages on the site that are stored in cookies. Once they reach the contact form and submit the form, the links to those previously visited pages are added to the body of the email.','cf7-visited-pages-url-tracking'); ?> (<a href="<?php echo esc_url(plugin_dir_url( __FILE__ ) . 'images/visited-pages-cookie.png');?>" target="_blank"><?php esc_html_e( 'screenshot', 'cf7-visited-pages-url-tracking' ); ?></a>)</p>