fix: correct Mermaid diagram rendering in Antora site (#20)

- Change block syntax from [kroki,mermaid] to [mermaid]
- Remove kroki-fetch-diagram attribute from both playbooks

Signed-off-by: jimisola <jimisola@jimisola.com>
Co-authored-by: Jimisola Laursen <jimisola.laursen@resurs.se>

Author: jimisola

docs/antora-playbook.yml

@@ -54,7 +54,6 @@ asciidoc:
     idseparator: "-"
     page-pagination: ""
     kroki-server-url: https://kroki.io
-    kroki-fetch-diagram: true
     allow-uri-read: true
     sectnumlevels: 4
     toclevels: 3

docs/local-antora-playbook.yml

@@ -55,7 +55,6 @@ asciidoc:
     idseparator: "-"
     page-pagination: ""
     kroki-server-url: https://kroki.io
-    kroki-fetch-diagram: true
     allow-uri-read: true
     sectnumlevels: 4
     toclevels: 3

docs/modules/ROOT/pages/index.adoc

@@ -12,7 +12,7 @@ reqstool is an open-source toolchain for managing software requirements with ful
 
 == How it works
 
-[kroki,mermaid]
+[mermaid]
 ....
 graph LR
     A["Requirements (YAML)"] --> B["Annotations (@Requirements, @SVCs)"]