README: actually actually fix markup

rst is the worst format ever, so hypertext links and bold somehow
do not mix. I've tried like, every variation. What a mess.

Author: CounterPillow

README.rst

@@ -18,8 +18,11 @@ Blog:
 
 **PLEASE NOTE: Overviewer is currently unmaintained. PRs will not be merged
 and issues will not be addressed. The website and repository will remain online
-and accessible. For an alternative, please consider using
-`BlueMap <https://bluemap.bluecolored.de/>`_**
+and accessible.**
+
+For an alternative, please consider using `BlueMap`_ instead.
+
+.. _BlueMap: https://bluemap.bluecolored.de/
 
 The Minecraft Overviewer is a command-line tool for rendering high-resolution
 maps of Minecraft worlds. It generates a set of static html and image files and