doc/go1.15: add encoding/asn1 note about minimal encoding

Also fix missing <code> tags in the other encoding/asn1 note.

Updates #37419

Change-Id: Ic0e9131016b44ed864629aa8d0a7fddb57146d21
Reviewed-on: https://go-review.googlesource.com/c/go/+/240518
Reviewed-by: Filippo Valsorda <[email protected]>

Author: rolandshoemaker

doc/go1.15.html

@@ -598,9 +598,14 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
 <dl id="encoding/asn1"><dt><a href="/pkg/encoding/asn1/">encoding/asn1</a></dt>
   <dd>
     <p><!-- CL 226984 -->
-      <a href="/pkg/encoding/asn1/#Marshal">Marshal</a> now sorts the components
+      <a href="/pkg/encoding/asn1/#Marshal"><code>Marshal</code></a> now sorts the components
       of SET OF according to X.690 DER.
     </p>
+
+    <p><!-- CL 227320 -->
+      <a href="/pkg/encoding/asn1/#Unmarshal"><code>Unmarshal</code></a> now rejects tags and
+      Object Identifiers which are not minimally encoded according to X.690 DER.
+    </p>
   </dd>
 </dl><!-- encoding/asn1 -->