Full JSON-RPC docs + sync tests. (#4335)

* Extended Markdown generator

* Synced and extended all JSON-RPC interfaces

* Fix linter errors

* Format `parity_listAccounts` output in API

* typo

* Check if interfaces are synced in JS spec tests

* Fixing missing interface errors

* Better #[rpc] attribute parsing

* Fixed RPC JS spec tests

* More examples

* Refactored how dummy data appears in examples

* Complete trace docs!

* fix typo

* Less copy-paste

* All the docs!

* Fix differences between CallRequest and TransactionRequest

* Fix differences between CallRequest and TransactionRequest

* Missing examples

* Grumble fixes