fixed link in sect 3.3 (after "description")

ch03.adoc

@@ -98,11 +98,11 @@ The description may define rules on the variable type, attributes and coordinate
 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
-https://cfconventions.org/Data/cf-standard-names/current/src/cf-standard-name-table.xml,
+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>>.
 Knowledge of the XML format is only necessary for application writers who plan to directly access the table.
 A formatted text version of the table is provided at
-https://cfconventions.org/Data/cf-standard-names/current/build/cf-standard-name-table.html,
+link:$$https://cfconventions.org/Data/cf-standard-names/current/build/cf-standard-name-table.html$$[https://cfconventions.org/Data/cf-standard-names/current/build/cf-standard-name-table.html],
 and this table may be consulted in order to find the standard name that should be assigned to a variable.
 Some standard names (e.g. **`region`** and **`area_type`**) are used to indicate quantities which are permitted to take only certain standard values.
 This is indicated in the definition of the quantity in the standard name table, accompanied by a list or a link to a list of the permitted values.