Refactor og:description to limit the max length (#26876)

1. The `og:description` should be "a one to two sentence description of
your object"
* It shouldn't output all the user inputted content -- it would be
pretty huge.
    * Maybe it only needs at most 300 bytes.
2. Do not render commit message as HTML

modules/templates/util_string.go

@@ -33,6 +33,11 @@ func (su *StringUtils) Join(a []string, sep string) string {
 	return strings.Join(a, sep)
 }
 
+func (su *StringUtils) Cut(s, sep string) []any {
+	before, after, found := strings.Cut(s, sep)
+	return []any{before, after, found}
+}
+
 func (su *StringUtils) EllipsisString(s string, max int) string {
 	return base.EllipsisString(s, max)
 }