Add accTitle and accDescr parameters to sample diagrams

[amyq]

Is your feature request related to a problem? Please describe.

I was unaware that all diagrams supported the accTitle and accDescr parameters to improve accessibility. Shouldn't the live editor encourage accessibility by default, by including these parameters in each of the sample diagrams?

(see https://mermaid.js.org/config/accessibility.html#accessible-title-and-description)

Describe the solution you'd like

Each of the sample diagrams should be updated to include accTitle and accDescr parameters. This would encourage more users to use them by default.

Describe alternatives you've considered

There really isn't one, except learning on your own that https://mermaid.js.org/config/accessibility.html exists.

Additional context
Add any other context or screenshots about the feature request here.