docs: add a "front matter" snippet to our markdown pages

It turns out Jekyll (the engine behind GitHub Pages) requires that pages
include a "Front Matter" snippet of YAML at the top for proper rendering.

Omitting it will still render the pages, but including it opens up new
possibilities, such as using a {% for %} loop to generate index.md instead of
requiring a separate script.

I'm hoping this will also fix the issue with some of the pages (notably
CODE_OF_CONDUCT.html) not being available under systemd.io

Tested locally by rendering the website with Jekyll. Before this change, the
*.md files were kept unchanged (so not sure how that even works?!), after this
commit, proper *.html files were generated from it.

docs/AUTOMATIC_BOOT_ASSESSMENT.md

@@ -1,3 +1,7 @@
+---
+title: Automatic Boot Assessment
+---
+
 # Automatic Boot Assessment
 
 systemd provides support for automatically reverting back to the previous

docs/BLOCK_DEVICE_LOCKING.md

@@ -1,3 +1,7 @@
+---
+title: Locking Block Device Access
+---
+
 # Locking Block Device Access
 
 *TL;DR: Use BSD file locks

docs/BOOT_LOADER_INTERFACE.md

@@ -1,3 +1,7 @@
+---
+title: The Boot Loader Interface
+---
+
 # The Boot Loader Interface
 
 systemd can interface with the boot loader to receive performance data and

docs/BOOT_LOADER_SPECIFICATION.md

@@ -1,3 +1,7 @@
+---
+title: The Boot Loader Specification
+---
+
 # The Boot Loader Specification
 
 _TL;DR: Currently there's little cooperation between multiple distributions in dual-boot (or triple, ... multi-boot) setups, and we'd like to improve this situation by getting everybody to commit to a single boot configuration format that is based on drop-in files, and thus is robust, simple, works without rewriting configuration files and is free of namespace clashes._

docs/CGROUP_DELEGATION.md

@@ -1,3 +1,7 @@
+---
+title: Control Group APIs and Delegation
+---
+
 # Control Group APIs and Delegation
 
 *Intended audience: hackers working on userspace subsystems that require direct

docs/CODE_OF_CONDUCT.md

@@ -1,3 +1,7 @@
+---
+title: The systemd Community Conduct Guidelines
+---
+
 # The systemd Community Conduct Guidelines
 
 This document provides community guidelines for a safe, respectful, productive, and collaborative place for any person who is willing to contribute to systemd. It applies to all “collaborative spaces”, which is defined as community communications channels (such as mailing lists, submitted patches, commit comments, etc.).

docs/CODE_QUALITY.md

@@ -1,3 +1,7 @@
+---
+title: Code Quality Tools
+---
+
 # Code Quality Tools
 
 The systemd project has a number of code quality tools set up in the source

docs/CODING_STYLE.md

@@ -1,3 +1,7 @@
+---
+title: Coding Style
+---
+
 # Coding Style
 
 - 8ch indent, no tabs, except for files in `man/` which are 2ch indent,

docs/CONTRIBUTING.md

@@ -1,3 +1,7 @@
+---
+title: Contributing
+---
+
 # Contributing
 
 We welcome contributions from everyone. However, please follow the following guidelines when posting a GitHub Pull Request or filing a GitHub Issue on the systemd project:

docs/DISTRO_PORTING.md

@@ -1,3 +1,7 @@
+---
+title: Porting systemd To New Distributions
+---
+
 # Porting systemd To New Distributions
 
 ## HOWTO

docs/ENVIRONMENT.md

@@ -1,3 +1,7 @@
+---
+title: Known Environment Variables
+---
+
 # Known Environment Variables
 
 A number of systemd components take additional runtime parameters via

docs/HACKING.md

@@ -1,3 +1,7 @@
+---
+title: Hacking on systemd
+---
+
 # Hacking on systemd
 
 We welcome all contributions to systemd. If you notice a bug or a missing

docs/PORTABLE_SERVICES.md

@@ -1,3 +1,7 @@
+---
+title: Portable Services Introduction
+---
+
 # Portable Services Introduction
 
 This systemd version includes a preview of the "portable service"

docs/PREDICTABLE_INTERFACE_NAMES.md

@@ -1,3 +1,7 @@
+---
+title: Predictable Network Interface Names
+---
+
 # Predictable Network Interface Names
 
 Starting with v197 systemd/udev will automatically assign predictable, stable network interface names for all local Ethernet, WLAN and WWAN interfaces. This is a departure from the traditional interface naming scheme ("eth0", "eth1", "wlan0", ...), but should fix real problems.

docs/RELEASE.md

@@ -1,3 +1,7 @@
+---
+title: Steps to a Successful Release
+---
+
 # Steps to a Successful Release
 
 1. Add all items to NEWS

docs/TRANSIENT-SETTINGS.md

@@ -1,3 +1,7 @@
+---
+title: What settings are currently available for transient units?
+---
+
 # What settings are currently available for transient units?
 
 Our intention is to make all settings that are available as unit file settings

docs/TRANSLATORS.md

@@ -1,3 +1,7 @@
+---
+title: Notes for Translators
+---
+
 # Notes for Translators
 
 systemd depends on the `gettext` package for multilingual support.

docs/UIDS-GIDS.md

@@ -1,3 +1,7 @@
+---
+title: Users, Groups, UIDs and GIDs on `systemd` Systems
+---
+
 # Users, Groups, UIDs and GIDs on `systemd` Systems
 
 Here's a summary of the requirements `systemd` (and Linux) make on UID/GID

docs/index.md

@@ -1,3 +1,7 @@
+---
+title: systemd Documentation
+---
+
 # systemd Documentation
 
 * [Automatic Boot Assessment](https://systemd.io/AUTOMATIC_BOOT_ASSESSMENT)