message: doc: Fix broken link in doc/build-osx.md
  This fixes the regression in PR as noted here:
diff: @@ -112,7 +112,7 @@ tail -f $HOME/Library/Application\ Support/Bitcoin/debug.log
  ## Notes
  * Tested on OS X 10.10 Yosemite through macOS 10.14 Mojave on 64-bit Intel
  processors only.
  -* Building with downloaded Qt binaries is not officially supported. See the notes in [#7714](https://github.com/bitcoin/issues/7714)
  +* Building with downloaded Qt binaries is not officially supported. See the notes in [#7714](https://github.com/bitcoin/bitcoin/issues/7714).
  ## Deterministic macOS DMG Notes
  Working macOS DMGs are created in Linux by combining a recent `clang`, the Apple
  