add missing language string when capabilities are displayed.

lang/en/tiny_htmlblock.php

@@ -31,6 +31,7 @@
 $string['dlgintro'] = 'Select one of these blocks to insert it at the current position. Placeholder texts can be modified once the block is inserted.';
 $string['dlginsert'] = 'Insert';
 $string['helplinktext'] = 'HTML Blocks';
+$string['htmlblock:viewmenu'] = 'Add predefined HTML blocks in editor';
 $string['labelaction'] = 'Action';
 $string['labelcat'] = 'Category';
 $string['labelname'] = 'Name';