Improved documentation.

Removed the Cookbook link for now, since it's empty.

mkdocs.yml

@@ -7,7 +7,6 @@ strict: true
 pages:
   - Introduction: index.md
   - Getting Started: GettingStarted.md
-  - Cookbook.md
   - FAQ:
     - Basics: FAQBasics.md
     - Semantics: FAQSemantics.md
@@ -15,14 +14,15 @@ pages:
     - Parallel Builds: FAQParallel.md
     - Implementation Details: FAQImpl.md
   - Contributing.md
-  - Command Reference (man pages):
-    - redo: redo.md
-    - redo-ifchange: redo-ifchange.md
-    - redo-ifcreate: redo-ifcreate.md
-    - redo-always: redo-always.md
-    - redo-stamp: redo-stamp.md
-    - redo-sources: redo-sources.md
-    - redo-targets: redo-targets.md
-    - redo-ood: redo-ood.md
-    - redo-whichdo: redo-whichdo.md
-    - redo-log: redo-log.md
+  - Reference:
+    - Manual Pages:
+      - redo: redo.md
+      - redo-ifchange: redo-ifchange.md
+      - redo-ifcreate: redo-ifcreate.md
+      - redo-always: redo-always.md
+      - redo-stamp: redo-stamp.md
+      - redo-sources: redo-sources.md
+      - redo-targets: redo-targets.md
+      - redo-ood: redo-ood.md
+      - redo-whichdo: redo-whichdo.md
+      - redo-log: redo-log.md