pref_prefs: mention that tt-rss server time is UTC

classes/pref_prefs.php

@@ -474,7 +474,7 @@ class Pref_Prefs extends Protected_Handler {
 				print "<input dojoType=\"dijit.form.ValidationTextBox\"
 					id=\"$pref_name\" regexp=\"[012]?\d:\d\d\" placeHolder=\"12:00\"
 					name=\"$pref_name\" value=\"$value\"><div class=\"insensitive\">".
-					T_sprintf("Current server time: %s", date("H:i")) . "</div>";
+					T_sprintf("Current server time: %s (UTC)", date("H:i")) . "</div>";
 			} else {
 				$regexp = ($type_name == 'integer') ? 'regexp="^\d*$"' : '';