Document where Confluence Cypress tests are missing coverage for existing Editor content types (nodes, marks)

See PIR for context: https://product-fabric.atlassian.net/wiki/spaces/E/pages/3174606383/DRAFT+HOT-97965+-+Data+loss+in+confluence+when+links+encountered+inside+code+snippets.

Task: As part of improving tested document on-load scenarios in product, investigate and document which Editor content types are missing from Confluence's existing Cypress integration test coverage. 

Use the current published (full) ADF schema as a source of truth/checklist for known supported content types, in order to determine what content is not being tested.

As a follow up task, decide which of these content scenarios (based on importance of the content type, testing effort) needs to be added to the existing Cypress test suite.