rna-transcription: add reference to tutorial

[FridaTveit]

We've decided that every exercise with difficulty less than 3 should reference the tutorial provided with the hello world exercise. This should make it easier for people to solve those early exercise. See issue #1389 for discussion.

So please add a hints.md file in https://github.com/exercism/java/tree/master/exercises/rna-transcription/.meta with a link to the hello world tutorial and a brief explanation of what it is (e.g. "For more help on how to solve this exercise, please refer to the tutorial provided as part of the hello world exercise").

Once the hints.md file has been added, the README for that exercise needs to be regenerated so that the hints are included. This can be done using configlet:

• Download configlet and put it somewhere in your PATH

• Clone the problem-specifications repository.

• Run configlet generate . --only rna-transcription --spec-path path_to_problem_specifications from the root of this repository.

[sjwarner-bp]

Closed via #1437