Strip HTML comments from RSS feed descriptions

Description

HTML comments (e.g., <!--FULLCONTENT-->, <!-- more -->) sometimes appear in RSS feed descriptions, making them visible to users in the RSS widget.

In internal/glance/widget-rss.go, add a regex pattern to strip HTML comments in sanitizeFeedDescription():

var htmlCommentsPattern = regexp.MustCompile(`<!--[\s\S]*?-->`)

I'd like to submit a PR for this if the approach looks good.