typo fix

src/10_xray.md

@@ -374,7 +374,7 @@ We have already learned how to construct Wigner-Seitz cells, however here is a r
 
 ## Diffraction
 
-### Reciprocal lattice Laue conditions
+### Reciprocal lattice: Laue conditions
 
 Reciprocal lattice manifests directly in the diffraction experiments.
 A diffraction experiment uses the crystal as a target and scatters high energy particles (X-rays, neutrons, or electrons) off of it.