Added explanation to block_rss_client_timeout. MDL-9292. Credit goes to Mike! B-)

lang/en_utf8/block_rss_client.php

@@ -40,7 +40,7 @@ $string['seeallfeeds'] = 'See all feeds';
 $string['sharedfeed'] = 'Shared feed';
 $string['shownumentrieslabel'] = 'Max number entries to show per block.';
 $string['submitters'] = 'Who will be allowed to define new rss feeds? Defined feeds are available for any page on your site.';
-$string['timeout'] = 'blockrsstimeout';
+$string['timeout'] = 'Time in minutes before an RSS feed expires in cache. Note that this time defines the minimum time before expiry; the feed will be refreshed in cache on the next cron execution after expiry. Recommended values are 30 mins or greater.';
 $string['timeoutdesc'] = 'Time in minutes for an RSS feed to live in cache.';
 $string['updatefeed'] = 'Update a news feed URL:';
 $string['validatefeed'] = 'Validate feed';