Recommend full_length parameters

Author: CZDanol

data/main_fields.yaml

@@ -158,6 +158,7 @@
 
 - key: 53
   name: nominal_full_length
+  required: recommended
   category: fff
   type: number
   unit: mm
@@ -168,6 +169,7 @@
 
 - key: 54
   name: actual_full_length
+  required: recommended
   category: fff
   type: number
   unit: mm
@@ -483,4 +485,4 @@
   description:
     - Recommended drying time (at `drying_temperature`).
 
-# First unused key: 59
+# First unused key: 59