docs: fix line breaks around elements in markdown

Ensure consistent line breaks around headings, lists and code blocks.

To make them more readable and also more portable (which could help when
previewing/converting files locally).

From the CommonMark Spec (version 0.30, published on 2021-06-19)[1]:

> 1.2 Why is a spec needed?

[...]

> 2. Is a blank line needed before a block quote or heading?  Most
>    implementations do not require the blank line.  However, this can
>    lead to unexpected results in hard-wrapped text, and also to
>    ambiguities in parsing (note that some implementations put the
>    heading inside the blockquote, while others do not).  (John Gruber
>    has also spoken in favor of requiring the blank lines.)[2]
>
> 3. Is a blank line needed before an indented code block?
>    (`Markdown.pl` requires it, but this is not mentioned in the
>    documentation, and some implementations do not require it.)

Fixes[3]:

* MD022 Headers should be surrounded by blank lines
* MD031 Fenced code blocks should be surrounded by blank lines
* MD032 Lists should be surrounded by blank lines

Environment: ruby-mdl 0.12.0-1 on Artix Linux.

[1] https://spec.commonmark.org/0.30/#why-is-a-spec-needed-
[2] http://article.gmane.org/gmane.text.markdown.general/2146
[3] https://github.com/markdownlint/markdownlint/blob/main/docs/RULES.md

1 files changed, 11 insertions, 2 deletions

diff --git a/README.md b/README.md
index 60e2d0ce8..175975cea 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,5 @@
 # Firejail
+
 [![Build Status](https://gitlab.com/Firejail/firejail_ci/badges/master/pipeline.svg)](https://gitlab.com/Firejail/firejail_ci/pipelines/)
 [![CodeQL](https://github.com/netblue30/firejail/workflows/CodeQL/badge.svg)](https://github.com/netblue30/firejail/actions?query=workflow%3ACodeQL)
 [![Build CI](https://github.com/netblue30/firejail/workflows/Build%20CI/badge.svg)](https://github.com/netblue30/firejail/actions?query=workflow%3A%22Build+CI%22)
@@ -114,12 +115,15 @@ $ git clone https://github.com/netblue30/firejail.git
 $ cd firejail
 $ ./configure && make && sudo make install-strip
 `````
+
 On Debian/Ubuntu you will need to install git and gcc compiler. AppArmor
 development libraries and pkg-config are required when using `--enable-apparmor`
 ./configure option:
+
 `````
 $ sudo apt-get install git build-essential libapparmor-dev pkg-config gawk
 `````
+
 For `--selinux` option, add libselinux1-dev (libselinux-devel for Fedora).
 
 Detailed information on using firejail from git is available on the [wiki](https://github.com/netblue30/firejail/wiki/Using-firejail-from-git).
@@ -134,7 +138,9 @@ $ firejail transmission-gtk   # starting Transmission BitTorrent
 $ firejail vlc                # starting VideoLAN Client
 $ sudo firejail /etc/init.d/nginx start
 `````
+
 Run `firejail --list` in a terminal to list all active sandboxes. Example:
+
 `````
 $ firejail --list
 1617:netblue:/usr/bin/firejail /usr/bin/firefox-esr
@@ -147,6 +153,7 @@ $ firejail --list
 ## Desktop integration
 
 Integrate your sandbox into your desktop by running the following two commands:
+
 `````
 $ firecfg --fix-sound
 $ sudo firecfg
@@ -169,7 +176,6 @@ You can find the profiles for all supported applications in [/etc/firejail](http
 If you keep additional Firejail security profiles in a public repository, please give us a link:
 
 * https://github.com/chiraag-nataraj/firejail-profiles
-
 * https://github.com/triceratops1/fe
 
 Use this issue to request new profiles: [#1139](https://github.com/netblue30/firejail/issues/1139)
@@ -183,6 +189,7 @@ We also keep a list of profile fixes for previous released versions in [etc-fixe
 ## Current development version: 0.9.73
 
 ### --keep-shell-rc
+
 `````
        --keep-shell-rc
               By default, when using a private home directory, firejail copies
@@ -190,10 +197,10 @@ We also keep a list of profile fixes for previous released versions in [etc-fixe
               which overrides attempts to whitelist the original  files  (such
               as  ~/.bashrc and ~/.zshrc).  This option disables this feature,
               and enables the user to whitelist the original files.
-
 `````
 
 ### private-etc rework
+
 `````
        --private-etc, --private-etc=file,directory,@group
               The files installed by --private-etc are copies of the original
@@ -226,6 +233,7 @@ We also keep a list of profile fixes for previous released versions in [etc-fixe
 
               $ strace /usr/bin/transmission-qt 2>&1 | grep open | grep etc
 `````
+
 We keep the list of groups in [src/include/etc_groups.h](https://github.com/netblue30/firejail/blob/master/src/include/etc_groups.h)
 Discussion: https://github.com/netblue30/firejail/discussions/5610
 
@@ -233,6 +241,7 @@ Discussion: https://github.com/netblue30/firejail/discussions/5610
 
 A small tool to print profile statistics. Compile and install as usual. The tool is installed in /usr/lib/firejail directory.
 Run it over the profiles in /etc/profiles:
+
 ```
 $ /usr/lib/firejail/profstats /etc/firejail/*.profile
 No include .local found in /etc/firejail/noprofile.profile