add headers to sidebar

Author: mohamed82008

docs/make.jl

@@ -6,7 +6,16 @@ makedocs(
     pages = [
         "Getting started" => "index.md",
         "Problem definition" => "problem/problem.md",
-        "Gradients, Jacobians and Hessians" => "gradients/gradients.md",
+        "Gradients, Jacobians and Hessians" => [
+            "Overview" => "gradients/gradients.md",
+            "user_defined.md",
+            "other_ad.md",
+            "chainrules_fd.md",
+            "sparse.md",
+            "symbolic.md",
+            "implicit.md",
+            "history.md",
+        ],
         "Algorithms" => [
             "Overview" => "algorithms/algorithms.md",
             "algorithms/mma.md",