Standards.ASN1: Added some AutoDoc mk II markup.

Also added some other comments.

lib/modules/Standards.pmod/ASN1.pmod/Types.pmod

@@ -1182,20 +1182,30 @@ class VisibleString {
   constant type_name = "VisibleString";
 }
 
+//! UTCTime
 //!
+//! RFC 2459 4.1.2.5.1
 class UTC
 {
   inherit String;
   constant tag = 23;
   constant type_name = "UTCTime";
 
+  //!
   this_program set_posix(int t)
   {
     object second = Calendar.ISO_UTC.Second(t);
 
-    // FIXME: What is this based on?
+    // RFC 2459 4.1.2.5.1:
+    //
+    // Where YY is greater than or equal to 50, the year shall be
+    // interpreted as 19YY; and
+    //
+    // Where YY is less than 50, the year shall be interpreted as 20YY.
     if (second->year_no() >= 2050)
       error( "Times later than 2049 not supported.\n" );
+    if (second->year_no() < 1950)
+      error( "Times earlier than 1950 not supported.\n" );
 
     value = sprintf("%02d%02d%02d%02d%02d%02dZ",
                     [int]second->year_no() % 100,
@@ -1207,6 +1217,7 @@ class UTC
     return this;
   }
 
+  //!
   int get_posix()
   {
     if( !value || sizeof(value)!=13 ) error("Data not UTC date string.\n");

lib/modules/Standards.pmod/PKCS.pmod/CSR.pmod

@@ -6,6 +6,11 @@
 
 import Standards.ASN1.Types;
 
+// NOTE: RFC 2314 6.1 says that the tag is IMPLICIT, and
+//       RFC 2986 4.1 says that the tag is EXPLICIT!
+//
+// OpenSSL seems to use IMPLICIT tagging,
+// so this is probably correct.
 //!
 class CRIAttributes
 {

lib/modules/Standards.pmod/X509.pmod

@@ -283,7 +283,7 @@ protected mapping(int:program(Object)) x509_types = ([
 //!
 //! @note
 //!   Was not compatible with @[Standards.ASN1.Types.Sequence]
-//!   Prior to Pike 8.0.
+//!   prior to Pike 8.0.
 class TBSCertificate
 {
   inherit Sequence;
@@ -910,7 +910,7 @@ class TBSCertificate
   int(0..1) ext_basicConstraints_cA;
 
   //! The maximum number of certificates that may follow this
-  //! certificate in a certificate chain. @exp{0@} in case no limit is
+  //! certificate in a certificate chain. @expr{0@} in case no limit is
   //! imposed. Note that this variable is off by one compared to the
   //! RFC 3280 definition, which only counts intermediate certificates
   //! (i.e. 0 intermediates means this variable would be 1, as in one