Missing t() string

The string "Enter a keyword." it's not translatable.

This line of the search-theme-form.tpl.php file:

$search['search_theme_form'] = '<div class="form-item" id="edit-search-theme-form-wrapper"><input type="text" maxlength="128" name="search_theme_form" id="edit-search-theme-form-1" size="15" value="Enter a keyword." title="Enter a keyword." onblur="this.value=this.value||this.defaultValue; this.style.color = \'#C6BBB3\';" onfocus="this.value=\'\'; this.style.color = \'#F1EAE5\';" class="form-text default-value" /></div>'; 

should be:

$search['search_theme_form'] = '<div class="form-item" id="edit-search-theme-form-wrapper"><input type="text" maxlength="128" name="search_theme_form" id="edit-search-theme-form-1" size="15" value="'.t('Enter a keyword.').'" title="Enter a keyword." onblur="this.value=this.value||this.defaultValue; this.style.color = \'#C6BBB3\';" onfocus="this.value=\'\'; this.style.color = \'#F1EAE5\';" class="form-text default-value" /></div>';