style: add comments to docker-gen template

Author: buchdag

app/letsencrypt_service_data.tmpl

@@ -3,11 +3,13 @@ LETSENCRYPT_CONTAINERS=(
         {{ if trim $hosts }}
             {{ range $container := $containers }}
                 {{ if parseBool (coalesce $container.Env.LETSENCRYPT_SINGLE_DOMAIN_CERTS "false") }}
+                    {{/* Explicit per-domain splitting of the certificate */}}
                     {{ range $host := split $hosts "," }}
                         {{ $host := trim $host }}
                         {{- "\t"}}'{{ printf "%.12s" $container.ID }}_{{ sha1 $host }}'
                     {{ end }}
                 {{ else }}
+                    {{/* Default: multi-domain (SAN) certificate */}}
                     {{- "\t"}}'{{ printf "%.12s" $container.ID }}'
                 {{ end }}
             {{ end }}
@@ -18,6 +20,7 @@ LETSENCRYPT_CONTAINERS=(
 {{ range $hosts, $containers := groupBy $ "Env.LETSENCRYPT_HOST" }}
     {{ $hosts := trimSuffix "," $hosts }}
     {{ range $container := $containers }}
+        {{/* Trim spaces and set empty values on per-container environment variables */}}
         {{ $KEYSIZE := trim (coalesce $container.Env.LETSENCRYPT_KEYSIZE "") }}
         {{ $STAGING := trim (coalesce $container.Env.LETSENCRYPT_TEST "") }}
         {{ $EMAIL := trim (coalesce $container.Env.LETSENCRYPT_EMAIL "") }}
@@ -30,6 +33,7 @@ LETSENCRYPT_CONTAINERS=(
         {{ $RESTART_CONTAINER := trim (coalesce $container.Env.LETSENCRYPT_RESTART_CONTAINER "") }}
         {{ $cid := printf "%.12s" $container.ID }}
         {{ if parseBool (coalesce $container.Env.LETSENCRYPT_SINGLE_DOMAIN_CERTS "false") }}
+            {{/* Explicit per-domain splitting of the certificate */}}
             {{ range $host := split $hosts "," }}
                 {{ $host := trim $host }}
                 {{ $host := trimSuffix "." $host }}
@@ -47,6 +51,7 @@ LETSENCRYPT_CONTAINERS=(
                 {{- "\n" }}LETSENCRYPT_{{ $cid }}_{{ $hostHash }}_RESTART_CONTAINER="{{ $RESTART_CONTAINER }}"
             {{ end }}
         {{ else }}
+            {{/* Default: multi-domain (SAN) certificate */}}
             {{- "\n" }}LETSENCRYPT_{{ $cid }}_HOST=( 
                     {{- range $host := split $hosts "," }}
                         {{- $host := trim $host }}