Removed page summaries from the top of installation and contributing doc pages (#10711)

- Removed page summaries from CONTRIBUTING and installation pages as 
this information was already in the table of contents on the right hand side
- Fixed some broken links in CONTRIBUTING
- Added margin-right tag for when table of contents is being shown
(otherwise the text in the page sometimes overlaps with it)

2 files changed, 6 insertions, 40 deletions

diff --git a/docs/setup/installation.md b/docs/setup/installation.md

index 8540a7b0c1..06f869cd75 100644
--- a/docs/setup/installation.md
+++ b/docs/setup/installation.md
@@ -1,44 +1,5 @@
 # Installation Instructions
 
-There are 3 steps to follow under **Installation Instructions**.
-
-- [Installation Instructions](#installation-instructions)
-  - [Choosing your server name](#choosing-your-server-name)
-  - [Installing Synapse](#installing-synapse)
-    - [Installing from source](#installing-from-source)
-      - [Platform-specific prerequisites](#platform-specific-prerequisites)
-        - [Debian/Ubuntu/Raspbian](#debianubunturaspbian)
-        - [ArchLinux](#archlinux)
-        - [CentOS/Fedora](#centosfedora)
-        - [macOS](#macos)
-        - [OpenSUSE](#opensuse)
-        - [OpenBSD](#openbsd)
-        - [Windows](#windows)
-    - [Prebuilt packages](#prebuilt-packages)
-      - [Docker images and Ansible playbooks](#docker-images-and-ansible-playbooks)
-      - [Debian/Ubuntu](#debianubuntu)
-        - [Matrix.org packages](#matrixorg-packages)
-        - [Downstream Debian packages](#downstream-debian-packages)
-        - [Downstream Ubuntu packages](#downstream-ubuntu-packages)
-      - [Fedora](#fedora)
-      - [OpenSUSE](#opensuse-1)
-      - [SUSE Linux Enterprise Server](#suse-linux-enterprise-server)
-      - [ArchLinux](#archlinux-1)
-      - [Void Linux](#void-linux)
-      - [FreeBSD](#freebsd)
-      - [OpenBSD](#openbsd-1)
-      - [NixOS](#nixos)
-  - [Setting up Synapse](#setting-up-synapse)
-    - [Using PostgreSQL](#using-postgresql)
-    - [TLS certificates](#tls-certificates)
-    - [Client Well-Known URI](#client-well-known-uri)
-    - [Email](#email)
-    - [Registering a user](#registering-a-user)
-    - [Setting up a TURN server](#setting-up-a-turn-server)
-    - [URL previews](#url-previews)
-    - [Troubleshooting Installation](#troubleshooting-installation)
-
-
 ## Choosing your server name
 
 It is important to choose the name for your server before you install Synapse,
diff --git a/docs/website_files/table-of-contents.css b/docs/website_files/table-of-contents.css

index d16bb3b988..1b6f44b66a 100644
--- a/docs/website_files/table-of-contents.css
+++ b/docs/website_files/table-of-contents.css
@@ -1,3 +1,7 @@
+:root {
+    --pagetoc-width: 250px;
+}
+
 @media only screen and (max-width:1439px) {
     .sidetoc {
         display: none;
@@ -8,6 +12,7 @@
     main {
         position: relative;
         margin-left: 100px !important;
+        margin-right: var(--pagetoc-width) !important;
     }
     .sidetoc {
         margin-left: auto;
@@ -18,7 +23,7 @@
     }
     .pagetoc {
         position: fixed;
-        width: 250px;
+        width: var(--pagetoc-width);
         overflow: auto;
         right: 20px;
         height: calc(100% - var(--menu-bar-height));