Missing References

[mjethanandani]

The latest version of this tool complains about missing references when it is regular text in the draft. For example if the text in the draft says the following:

   [64496 64500]
      Matches the AS_PATH where at least one of the ASes is either 64496
      or 64500.

   [^64496 64500]
      Matches the AS_PATH where neither 64496 nor 64500 are present in
      the AS_PATH.

   [64496-64511]
      Matches the AS_PATH where at least one AS number is in the range
      64496..64511, inclusive.  This matches the documentation AS
      numbers in [RFC5398].

The tools reports the following error:

  == Missing Reference: '64496 64500' is mentioned on line 7881, but
     not defined

  == Missing Reference: '64496-64511' is mentioned on line 7889, but
     not defined

  == Missing Reference: '64505-64511' is mentioned on line 7901, but
     not defined

[rjsparks]

We'll add this as a place to improve the behavior for the re-implementation of idnits.