fix video link

src/10_xray.md

@@ -53,7 +53,7 @@ _based on chapters 13.1-13.2 & 14.1-14.2 of the book_
     - Compute the intensity of X-ray diffraction of a given crystal
     - Interpret X-ray powder diffraction data
 
- ??? info "Lecture video"
+??? info "Lecture video"
 
     <iframe width="100%" height="315" src="https://www.youtube-nocookie.com/embed/0l8Z0p07YeM" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>