zoneparser: document not checking syntax (#1245)

* zoneparser: document not checking syntax

Add a couple of lines that we're not syntax checking.

Closes: #948

Signed-off-by: Miek Gieben <miek@miek.nl>

* Update wording after review.

Signed-off-by: Miek Gieben <miek@miek.nl>

scan.go

@@ -150,6 +150,9 @@ func ReadRR(r io.Reader, file string) (RR, error) {
 // The text "; this is comment" is returned from Comment. Comments inside
 // the RR are returned concatenated along with the RR. Comments on a line
 // by themselves are discarded.
+//
+// Callers should not assume all returned data in an Resource Record is
+// syntactically correct, e.g. illegal base64 in RRSIGs will be returned as-is.
 type ZoneParser struct {
 	c *zlexer