Update mkdocs.yml

mkdocs.yml

@@ -38,7 +38,7 @@ nav:
     # - Sommerfeld model: '4_sommerfeld_model_solutions.md'
     # - LCAO model: '5_atoms_and_lcao_solutions.md'
     # - Bonds and spectra: '6_bonds_and_spectra_solutions.md'
-    - Tight-binding model: '7_tight_binding_solutions.md'
+    - Tight-binding model: '7_tight_binding_model_solutions.md'
     - Many atoms per unit cell: '8_many_atoms_solutions.md'
     # - Crystal structure: '9_crystal_structure_solutions.md'
     # - X-ray diffraction: '10_xray_solutions.md'