Add missing doccontentref to older posts

I thought I committed them already. This is why you should really pay
attention to the build logs.

content/posts/2023-03-24-managing-mutable-files-in-nixos/index.adoc

@@ -10,6 +10,8 @@ tags:
 Gabriel Arazas <foodogsquared@foodogsquared.one>
 v1.0.2, 2023-04-07: Update quote description
 
+:doccontentref: refs/heads/content/posts/2023-03-24-managing-mutable-files-in-nixos
+
 :home-manager-rev: bb4b25b302dbf0f527f190461b080b5262871756
 :nix-flakes-post: ../2023-03-05-combining-traditional-dotfiles-and-nixos-configurations-with-nix-flakes/index.adoc
 

content/posts/2023-04-10-asciidoc-go-template-and-hugo-featuring-nix/index.adoc

@@ -12,6 +12,8 @@ tags:
 Gabriel Arazas <foodogsquared@foodogsquared.one>
 v1.0.3, 2023-04-11: Update the revision for the site source code
 
+:doccontentref: refs/heads/content/posts/2023-04-10-asciidoc-go-template-and-hugo-featuring-nix
+
 :swhid-hugo-docs-asciidoctor-extension-support: swh:1:cnt:a98898821c30a1554c300c909cd29600059f436a;origin=https://github.com/gohugoio/hugo;visit=swh:1:snp:41c409e12a0a2aee3dd77f3270736828b60dc5e6;anchor=swh:1:rev:f1e8f010f5f5990c6e172b977e5e2d2878b9a338;path=/docs/content/en/content-management/formats.md;lines=96
 :swhid-hugo-initial-asciidoctor-impl: swh:1:cnt:8cc3e79e67d7d197f5211c182f5a216b06c7cb9e;origin=https://github.com/gohugoio/hugo;visit=swh:1:snp:41c409e12a0a2aee3dd77f3270736828b60dc5e6;anchor=swh:1:rev:f0266e2ef3487bc57dd05402002fc816e3b40195;path=/markup/asciidocext/asciidocext_config/config.go;lines=34-42
 :foodogsquared-site-source-revision: 468ab1f841af6ab7ad8f197ac99f133f1ec60dc7
@@ -350,6 +352,7 @@ I wonder what that could be...
 The project mainly uses link:https://nixos.org/[Nix] to easily reproduce the development environment in a snap.
 Just list the required dependencies in `shell.nix` at the project root, run `nix-shell`, and voila!
 
+[.error]
 .`shell.nix`
 [source, nix]
 ----
@@ -399,7 +402,7 @@ This is the doing of `bundlerEnv` by including exported executables from the gem
 
 To check that it is working, enter the Nix environment with `nix-shell` and rerun the `asciidoctor` command.
 
-[.failed]
+[.error]
 [source, shell]
 ----
 asciidoctor -r asciidoctor-custom-extensions sample.adoc
@@ -408,6 +411,7 @@ asciidoctor -r asciidoctor-custom-extensions sample.adoc
 ...which you shouldn't be able to successfully run.
 Instead, you should have the following results similar to the next listing.
 
+[.error]
 [literal]
 ----
 include::./assets/bundlerenv-error[]

content/posts/2023-05-12-using-software-heritage-for-technical-writing/index.adoc

@@ -9,6 +9,8 @@ tags:
 Gabriel Arazas <foodogsquared@foodogsquared.one>
 v1.1.0, 2023-05-19: Corrected information and update descriptions
 
+:doccontentref: refs/heads/content/posts/2023-05-12-using-software-heritage-for-technical-writing
+
 include::./attributes.adoc[]
 
 

content/posts/2023-05-30-my-offline-music-streaming-setup/index.adoc

@@ -10,6 +10,8 @@ tags:
 Gabriel Arazas <foodogsquared@foodogsquared.one>
 v1.0.0, 2023-05-30: Initial version
 
+:doccontentref: refs/heads/content/posts/2023-05-30-my-offline-music-streaming-setup
+
 :swh-gonic-service-unit-contrib: swh:1:cnt:4a2128ff5d679b1eceac27464f2ccbd5c3dabc90;origin=https://github.com/sentriz/gonic;visit=swh:1:snp:c9ba117bcd80577fa6dbae0293c45e3d6488c08c;anchor=swh:1:rev:2f4ea6caa86afb8c78fda4efcd1d4a5e8aa18c60;path=/contrib/gonic.service
 :swh-gonic-service-nixpkgs: swh:1:cnt:65cf10f2c4b4623770b7006e927dc5838f3c7920;origin=https://github.com/NixOS/nixpkgs;visit=swh:1:snp:4b4f22375c9650345eb207a70c0158f951386514;anchor=swh:1:rev:1eae9f8f1b6a444b15d9037d4b8f2ca7da045a3f;path=/nixos/modules/services/audio/gonic.nix;lines=40-85