Some admin copy improvements fixes. #6362 props xenlab and ninjaWR.

git-svn-id: https://develop.svn.wordpress.org/trunk@12228 602fd350-edb4-49c9-b593-d223f7449a82

wp-admin/edit-link-categories.php

@@ -209,6 +209,7 @@ if ( $page_links )
 <div class="form-field">
 	<label for="description"><?php _e('Description (optional)') ?></label>
 	<textarea name="description" id="description" rows="5" cols="40"></textarea>
+	<p><?php _e('The description is not prominent by default; however, some themes may show it.'); ?></p>
 </div>
 
 <p class="submit"><input type="submit" class="button" name="submit" value="<?php esc_attr_e('Add Category'); ?>" /></p>