[gnomemm-website] CI: Add some comments in .gitlab-ci.yml

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 78407496aeac9e9d8db584a3fec683825d66db0c
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Sun Jan 9 15:58:30 2022 +0100

    CI: Add some comments in .gitlab-ci.yml

 .gitlab-ci.yml | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 7315c78..a3951b8 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -9,6 +9,9 @@ stages:
 website_build:
   stage: build
   variables:
+    # If docbook-xsl is installed, the xsltproc command reads
+    # stylesheets from local files instead of http://docbook.sourceforge.net.
+    # Faster and safer. Reading from docbook.sourceforge.net sometimes fails.
     DEPENDENCIES:
       autoconf
       yelp-tools
@@ -19,8 +22,6 @@ website_build:
       xsltproc
       docbook-xml
       docbook-xsl
-  #    docbook5-xml
-  #    docbook-xsl-ns
   script:
     - export DEBIAN_FRONTEND=noninteractive
     - apt update && apt -y upgrade && apt -y install $DEPENDENCIES