Update table of contents with new structure

Add syntax guide and contribution guides sections to toc.yml.
Organizes migrated content into logical hierarchy:

- Syntax guide with 37 markdown files
- Contribution guides organized by workflow (local, web, legacy)
- Documentation tools page
- How-to guides subsection with cumulative docs, file moves, and redirects

Author: leemthompo

contribute-docs/toc.yml

@@ -1,5 +1,61 @@
 toc:
   - file: index.md
+  - folder: contribute
+    children:
+      - file: index.md
+      - file: locally.md
+      - file: on-the-web.md
+      - file: legacy-docs.md
+      - file: tools.md
+      - folder: how-to
+        children:
+          - file: index.md
+          - folder: cumulative-docs
+            children:
+              - file: index.md
+              - file: guidelines.md
+              - file: badge-placement.md
+              - file: example-scenarios.md
+              - file: reference.md
+          - file: move.md
+          - file: redirects.md
+  - folder: syntax
+    children:
+      - file: index.md
+      - file: quick-ref.md
+      - file: directives.md
+      - file: admonitions.md
+      - file: applies.md
+      - file: applies-switch.md
+      - file: automated_settings.md
+      - file: code.md
+      - file: comments.md
+      - file: conditionals.md
+      - file: csv-include.md
+      - file: definition-lists.md
+      - file: diagrams.md
+      - file: dropdowns.md
+      - file: example_blocks.md
+      - file: file_inclusion.md
+      - file: frontmatter.md
+      - file: headings.md
+      - file: icons.md
+      - file: images.md
+      - file: kbd.md
+      - file: line_breaks.md
+      - file: links.md
+      - file: lists.md
+      - file: math.md
+      - file: passthrough.md
+      - file: sidebars.md
+      - file: stepper.md
+      - file: substitutions.md
+      - file: sundries.md
+      - file: tables.md
+      - file: tabs.md
+      - file: tagged_regions.md
+      - file: titles.md
+      - file: version-variables.md
   - folder: api-docs
     children:
       - file: index.md