remove reference to GRIB/AMIP code which no longer exist

ch03.adoc

@@ -175,8 +175,6 @@ description:: The description is meant to clarify the qualifiers of the fundamen
 We don't attempt to provide precise definitions of fundumental physical quantities (e.g., temperature) which may be found in the literature.
 The description may define rules on the variable type, attributes and coordinates which must be complied with by any variable carrying that standard name (such as in Example 3.5).
 
-When appropriate, the table entry also contains the corresponding GRIB parameter code(s) (from ECMWF and NCEP) and AMIP identifiers.
-
 The standard name table is located at
 link:$$https://cfconventions.org/Data/cf-standard-names/current/src/cf-standard-name-table.xml$$[https://cfconventions.org/Data/cf-standard-names/current/src/cf-standard-name-table.xml],
 written in compliance with the XML format, as described in <<standard-name-table-format>>.