Fix toctree in index.rst, coming from previous merge faults

Author: amotl

docs/index.rst

@@ -56,21 +56,17 @@ The legacy feature gallery exclusively uses reStructuredText.
 .. toctree::
     :maxdepth: 1
 
-    headings
     admonitions
+    codesnippets
+    diagrams
+    glossary
+    headings
+    images
     lists
-    subpage
     projects
+    subpage
     tables
     typography
-    tables
-    images
-    diagrams
-    codesnippets
-    typography
-    subpage
-    glossary
-    projects