Duplicate heading anchors

[reakaleek]

Describe the bug

If there are multiple headings with the same title e.g.

## Heading 1
### Example
## Heading 2
### Example

Then the table of contents navigation gets confused because there are multiple sections with the same id.

Expected behavior

Each heading should have a unique anchor

Steps to reproduce

No response

Tooling

• docs-builder
• migration tooling
• I'm not sure

[Mpdreamz]

Should this be an error?

[KOTungseth]

We should be using unique titles and anchors for each of our Docs pages.

We should error on this in the Docs build.

[bmorelli25]

Should this be an error?

Requires a hint phase so folks can clean up content before we start to warn.