message: doc: Clean out release notes after release
  Tree-SHA512:
diff: -Bitcoin Core version 0.16.3 is now available from:
  +Bitcoin Core version 0.16.x is now available from:
  - <https://bitcoincore.org/bin/bitcoin-core-0.16.3/>
  + <https://bitcoincore.org/bin/bitcoin-core-0.16.x/>
  This is a new minor version release, with various bugfixes
  as well as updated translations.
  @@ -49,42 +49,22 @@ frequently tested on them.
  Notable changes
  ===============
  -Denial-of-Service vulnerability
  --------------------------------
  +(to be filled in)
  -A denial-of-service vulnerability exploitable by miners has been discovered in
  -Bitcoin Core versions 0.14.0 up to 0.16.2. It is recommended to upgrade any of
  -the vulnerable versions to 0.16.3 as soon as possible.
  -
  -0.16.3 change log
  +0.16.x change log
  ------------------
  -### Consensus
  -- #14249 `696b936` Fix crash bug with duplicate inputs within a transaction (TheBlueMatt, sdaftuar)
  -
  -### RPC and other APIs
  -- #13547 `212ef1f` Make `signrawtransaction*` give an error when amount is needed but missing (ajtowns)
  -
  -### Miscellaneous
  -- #13655 `1cdbea7` bitcoinconsensus: invalid flags error should be set to `bitcoinconsensus_err` (afk11)
  -
  -### Documentation
  -- #13844 `11b9dbb` correct the help output for -prune (hebasto)
  +(to be filled in)
  Credits
  =======
  Thanks to everyone who directly contributed to this release:
  -- Anthony Towns
  -- Hennadii Stepanov
  -- Matt Corallo
  -- Suhas Daftuar
  -- Thomas Kerin
  -- Wladimir J. van der Laan
  +(to be filled in)
  And to those that reported security issues:
  -- beardnboobies
  +(to be filled in)
  As well as everyone that helped translating on [Transifex](https://www.transifex.com/projects/p/bitcoin/).
  