More clearly document that only needed fields should be listed

Author: matthijskooijman

README.md

@@ -136,6 +136,12 @@ fields in a generic way, for example to print the parse results with
 just a few lines of code. See the parse and read examples for how this
 works.
 
+Note that these examples contain the full list of supported fields,
+which causes parsing and printing code to be generated for all those
+fields, even if they are not present in the output you want to parse. It
+is recommended to limit the list of fields to just the ones that you
+need, to make the parsing and printing code smaller and faster.
+
 Parsed value types
 ------------------
 Some values are parsed to an Arduino `String` value or C++ integer type,

examples/parse/parse.ino

@@ -45,7 +45,9 @@ const char raw[] =
 
 /**
  * Define the data we're interested in, as well as the datastructure to
- * hold the parsed data.
+ * hold the parsed data. This list shows all supported fields, remove
+ * any fields you are not using from the below list to make the parsing
+ * and printing code smaller.
  * Each template argument below results in a field of the same name.
  */
 using MyData = ParsedData<

examples/read/read.ino

@@ -13,7 +13,9 @@
 
 /**
  * Define the data we're interested in, as well as the datastructure to
- * hold the parsed data.
+ * hold the parsed data. This list shows all supported fields, remove
+ * any fields you are not using from the below list to make the parsing
+ * and printing code smaller.
  * Each template argument below results in a field of the same name.
  */
 using MyData = ParsedData<