Set up mdbook in github pages (#26367)

.github/workflows/docs.yml

@@ -0,0 +1,52 @@
+name: Deploy documentation
+
+on:
+    push:
+        branches: [develop]
+    workflow_dispatch: {}
+
+jobs:
+    docs:
+        name: GitHub Pages
+        runs-on: ubuntu-latest
+        steps:
+            - name: Fetch element-desktop
+              uses: actions/checkout@v4
+              with:
+                  repository: vector-im/element-desktop
+                  path: element-desktop
+
+            - name: Fetch element-web
+              uses: actions/checkout@v4
+              with:
+                  path: element-web
+
+            - name: Fetch matrix-react-sdk
+              uses: actions/checkout@v4
+              with:
+                  repository: matrix-org/matrix-react-sdk
+                  path: matrix-react-sdk
+
+            - name: Setup mdBook
+              uses: peaceiris/actions-mdbook@v1
+              with:
+                  mdbook-version: "0.4.10"
+
+            - name: Install mdbook-combiner
+              run: cargo install mdbook-combiner
+
+            - name: Build docs
+              run: |
+                  mkdir docs
+                  mv element-desktop/docs docs/element-desktop
+                  mv element-web/docs docs/element-web
+                  mv matrix-react-sdk/docs docs/matrix-react-sdk
+                  mdbook-combiner -m docs
+                  cp element-web/book.toml .
+                  mdbook build
+
+            - name: Deploy to gh pages
+              uses: peaceiris/actions-gh-pages@373f7f263a76c20808c831209c920827a82a2847 # v3.9.3
+              with:
+                  github_token: ${{ secrets.GITHUB_TOKEN }}
+                  publish_dir: ./book

.gitignore

@@ -27,3 +27,4 @@ electron/pub
 # Auto-generated file
 /src/modules.ts
 /build_config.yaml
+/book

book.toml

@@ -0,0 +1,26 @@
+# Documentation for possible options in this file is at
+# https://rust-lang.github.io/mdBook/format/config.html
+[book]
+title = "Element Web & Desktop"
+authors = ["New Vector Ltd.", "The Matrix.org Foundation C.I.C."]
+language = "en"
+multilingual = false
+
+# The directory that documentation files are stored in
+src = "docs"
+
+[build]
+# Prevent markdown pages from being automatically generated when they're
+# linked to in SUMMARY.md
+create-missing = false
+
+[output.html]
+# Remove the numbers that appear before each item in the sidebar, as they can
+# get quite messy as we nest deeper
+no-section-label = true
+
+# The source code URL of the repository
+git-repository-url = "https://github.com/vector-im/element-web"
+
+# The path that the docs are hosted on
+site-url = "/element-web/"

docs/SUMMARY.md

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+# Summary
+
+-   [Introduction](../README.md)
+
+# Usage
+
+-   [Betas](betas.md)
+-   [Labs](labs.md)
+
+# Setup
+
+-   [Config](config.md)
+-   [Custom home page](custom-home.md)
+-   [Kubernetes](kubernetes.md)
+-   [Jitsi](jitsi.md)
+-   [Encryption](e2ee.md)
+
+# Build
+
+-   [Customisations](customisations.md)
+-   [Modules](modules.md)
+-   [Native Node modules](native-node-modules.md)
+
+# Contribution
+
+-   [Choosing an issue](choosing-an-issue.md)
+-   [Translation](translating.md)
+-   [Netlify builds](pr-previews.md)
+-   [Code review](review.md)
+
+# Development
+
+-   [App load order](app-load.md)
+-   [Translation](translating-dev.md)
+-   [Theming](theming.md)
+-   [Memory profiling](memory-profiles-and-leaks.md)
+-   [Jitsi](jitsi-dev.md)
+-   [Feature flags](feature-flags.md)