docs(productions/default): add dictionary

Omitted from #338.

Author: saschanaz

README.md

@@ -638,13 +638,13 @@ Extended attributes look like this:
 Dictionary fields and operation arguments can take default values, and constants take
 values, all of which have the following fields:
 
-* `type`: One of string, number, boolean, null, Infinity, NaN, or sequence.
+* `type`: One of `"string"`, `"number"`, `"boolean"`, `"null"`, `"Infinity"`, `"NaN"`, `"sequence"` or `"dictionary"`.
 
-For string, number, boolean, and sequence:
+For `"string"`, `"number"`, `"boolean"`, and `"sequence"`:
 
 * `value`: The value of the given type, as a string. For sequence, the only possible value is `[]`.
 
-For Infinity:
+For `"Infinity"`:
 
 * `negative`: Boolean indicating whether this is negative Infinity or not.