message: [readme] Add docs link to the header table
diff: # pDSL - Parity's DSL for Smart Contracts
  -| Linux | Codecov | Coveralls | LoC |
  -|:------------------:|:--------------------:|:----------------------:|:----------------:|
  -| [![linux][A1]][A2] | [![codecov][C1]][C2] | [![coveralls][D1]][D2] | [![loc][E1]][E2] |
  +| Linux | Codecov | Coveralls | LoC | Docs |
  +|:------------------:|:--------------------:|:----------------------:|:----------------:|:-----------------:|
  +| [![linux][A1]][A2] | [![codecov][C1]][C2] | [![coveralls][D1]][D2] | [![loc][E1]][E2] | [![docs][F1]][F2] |
  [A1]: https://travis-ci.org/Robbepop/pdsl.svg?branch=master
  [A2]: https://travis-ci.org/Robbepop/pdsl
  [D2]: https://coveralls.io/github/Robbepop/pdsl?branch=master
  [E1]: https://tokei.rs/b1/github/Robbepop/pdsl?category=code
  [E2]: https://github.com/Aaronepower/tokei#badges
  +[F1]: https://img.shields.io/badge/docs-nightly-black.svg
  +[F2]: https://robbepop.github.io/pdsl/pdsl_core/index.html
  **IMPORTANT NOTE:** WORK IN PROGRESS! Do not expect this to be working.
  An [eDSL](https://wiki.haskell.org/Embedded_domain_specific_language) to write WebAssembly based smart contracts in the Rust programming language.
  -- [`pdsl-core` API documentation](https://robbepop.github.io/pdsl/pdsl_core/index.html).
  -
  ## Goals
  ### Core Goals
  