upgraded mermaid; added answer slide

_config.yml

_config_production.yml

_scss/mermaid/class.scss

_scss/mermaid/dark/index.scss

_scss/mermaid/default/index.scss

_scss/mermaid/flowchart.scss

_scss/mermaid/forest/index.scss

_scss/mermaid/gantt.scss

_scss/mermaid/git.scss

_scss/mermaid/mermaid.scss

_scss/mermaid/neutral/index.scss

_scss/mermaid/sequence.scss

assets/css/mermaid.css

assets/css/site.scss

assets/js/mermaid.8.8.2.js

assets/js/mermaid.js

slides/access-trees.html