Normalize notes about "packing process"?

[amilan17]

Do we need to keep these notes associated with the templates?  

21	For most templates, details of the packing process are described in Regulation 92.9.4.

Found in 

• TEMPLATE DEFINITIONS USED IN SECTION 5
• TEMPLATE DEFINITIONS USED IN SECTION 7

158	For most templates, details of the packing process are described in regulation 92.9.4.  This template is only valid for the Consultative Committee for Space Data Systems Recommendation for Space Data System Standards, Lossless Data Compression, CCSDS 121.0-B-2, Blue Book, May 2012.

Found in, should probably be two notes, if we keep it. 

• Data representation template 5.42 – Grid point and spectral data – CCSDS recommended lossless compression

Originally posted by @amilan17 in https://github.com/wmo-im/GRIB2/issues/118#issuecomment-924752250

[shahramn]

CCSDS is for GRID-POINT data not spectral