Update what's new.md

dist/preview release/what's new.md

@@ -20,7 +20,7 @@
     - New SPS property `computeBoundingBox` ([jerome](https://github.com/jbousquie))  
     - Added a new OnPickOut trigger fired when you release the pointer button outside of a mesh or sprite. ([deltakosh](https://github.com/deltakosh))
     - Added support for OnPointerOver and OnPointerOut for sprites. ([deltakosh](https://github.com/deltakosh))
-  - ** API doc **
+  - **API doc**
     - class `SolidParticleSystem` documented
     - class `MeshBuilder` documented
   - **Bug fixes**