fix(shortcuts): CTRL on windows or linux

public/app/core/components/help/help.html

@@ -22,7 +22,7 @@
 
 		<p class="small" style="position: absolute; top: 48px; right: 10px">
 			<span class="shortcut-table-key">mod</span> =
-			<span class="muted">CTRL on windows, CMD key on Mac</span>
+			<span class="muted">CTRL on windows or linux and CMD key on Mac</span>
 		</p>
 
 		<div ng-repeat="(category, shortcuts) in ctrl.shortcuts" class="shortcut-category">