Feature Request: Upon adding TOC, there should be a Dynamic Heading option

[andeng1106]

Is your feature request related to a problem? Please describe.
Yes. People are unable to use TOC block for widgets, sidebar, post templates, etc.

Describe the solution you'd like

• There should be a new option in TOC block named Dynamic Headings that should be enabled to get dynamic headings (e.g. TOC in sidebar gets the headings from site editor)
• Option Name: Dynamic Headings
  • Tooltip / Note: Use headings in current post
• If this is enabled:
  • should not be able to exclude heading
  • should not be able to click to type
  • should not show "Start adding Heading blocks to create..." upon adding a new TOC, if there's no headings yet in the current editor
    • instead, it should show sample entries
  • use PHP to parse the current page content and gather all blocks detected

Describe alternatives you've considered
Rewrite/re-word TOC block items manually