message: Add syntax highlighting to dependent record example
diff: - [Record values and record types](#record-values-and-record-types)
  - [Field lookups](#field-lookups)
  -- [Dependent record types](#dependent_record_types)
  +- [Dependent record types](#dependent-record-types)
  ## Record values and record types
  @@ -56,9 +56,9 @@ Field types can depend on data from previous fields. Here we turn a
  fixed-length array into a dynamically sized array, by using the `len` field
  later on to define the `data` field's annotation:
  -```
  +```pikelet
  DArray (a : Type) = Record {
  len : I32,
  data : Box (Array len a),
  -}
  +};
  ```
  