Switch to table-of-contents from menu

`menu` as a liquid variable wasn't working as of 11ty 1.0

Author: aaronshekey

docs/_includes/layouts/page.html

@@ -10,7 +10,7 @@
         {% include 'navigation.html' %}
 
         <main id="content" class="d-flex fl-grow1 ps-relative t64 py24 pl48 md:pl24 sm:pl16 sm:pr16">
-            {% if menu %}
+            {% if table-of-contents %}
                 <div class="flex--item order-last ml32 sm:d-none print:d-none" style="width: 14rem;">
                     <div class="ps-fixed t64 b0 py12 overflow-y-auto" style="width: 14rem;">
                         <h5 class="mt16 mb8 fw-bold tt-uppercase fs-fine fc-theme-primary mnl1">Sections</h5>

docs/email/guidelines/getting-started.html

@@ -2,7 +2,7 @@
 layout: page
 title: Email design at Stack Overflow
 description: An email design system that helps us work together to create consistently-designed, properly-rendered email for all Stack Overflow users. Intended for anyone who works with email at Stack Overflow.
-menu: false
+table-of-contents: false
 ---
 <section class="stacks-section">
     <div class="d-flex ai-center jc-space-between mb16 sm:fd-column sm:ai-start">

docs/email/templates/long-transactional.html

@@ -2,7 +2,7 @@
 layout: page
 title: Long transactional template
 description: A starter template for more complex transactional emails that could contain multiple messages. This template is meant to be adapted and built upon.
-menu: false
+table-of-contents: false
 ---
 <section class="stacks-section" data-controller="docs-resizer">
     <div class="d-flex jc-space-between ai-stretch gs16 gsx sm:fd-column">

docs/email/templates/major-announcements.html

@@ -2,7 +2,7 @@
 layout: page
 title: Major announcements
 description: Not all emails should look the same. Sometimes it’s appropriate to ditch the starter templates and design something unique. Here are a few emails we’ve sent for major announcements.
-menu: false
+table-of-contents: false
 ---
 {% tip %}
     <strong>Note:</strong> The source for these emails is provided for historical purposes only. It’s ok to grab <strong>parts</strong> of a design, but these templates should not be used as a starting point because the code is likely outdated.

docs/email/templates/promotional.html

@@ -2,7 +2,7 @@
 layout: page
 title: Promotional template
 description: A starter template for announcements, updates, and promotions. This template is meant to be adapted and built upon. If you’re working on a <strong>major announcement</strong>, consider <a href="{{ "/email/templates/major-announcements" | url }}">designing something&nbsp;unique</a>.
-menu: false
+table-of-contents: false
 ---
 <section class="stacks-section" data-controller="docs-resizer">
     <div class="d-flex jc-space-between ai-stretch gs16 gsx sm:fd-column">

docs/email/templates/short-transactional.html

@@ -2,7 +2,7 @@
 layout: page
 title: Short transactional template
 description: A  starter template for simple transactional emails with a single message. This template is meant to be adapted and built upon.
-menu: false
+table-of-contents: false
 ---
 
 <section class="stacks-section" data-controller="docs-resizer">