toml: add doc string to reflect methods (#12666)

vlib/toml/any.v

@@ -227,6 +227,8 @@ fn (a Any) value_(value Any, key []string) Any {
 	}
 }
 
+// reflect returns `T` with `T.<field>`'s value set to the
+// value of any 1st level TOML key by the same name.
 pub fn (a Any) reflect<T>() T {
 	mut reflected := T{}
 	$for field in T.fields {

vlib/toml/toml.v

@@ -173,6 +173,8 @@ pub fn (d Doc) to_any() Any {
 	return ast_to_any(d.ast.table)
 }
 
+// reflect returns `T` with `T.<field>`'s value set to the
+// value of any 1st level TOML key by the same name.
 pub fn (d Doc) reflect<T>() T {
 	return d.to_any().reflect<T>()
 }