fix: GitHub changed markdown rendering for headings/anchors

[handrews]

This is a rebase/re-submit of @MikeRalphson's exact commit from PR #3408 as he is not currently available to rebase it (the markdown checks were broken at that point on main- they should be fixed now).

Here is that PR's text:

---

Closes #3207 #3160 #3136 #3128 #3029 #3197 #3132

This PR mechanically corrects for the change made by GitHub to its markdown renderer which no longer honours the mixed markdown/html form:

### <a name="myAnchor"></a> My Anchor

(the use of name or id makes no difference), and only links to the implicit anchor #my-anchor now work.

This PR affects the main branch, so published versions of the OAS only. If merged, follow-up PRs will be raised for in-flight -dev branch versions.

An example of the result of this PR can be previewed here. [Note: points to @handrews's fork because of the re-submit]

[handrews]

So, what's going on here is this (all done by a script written by Mike Ralphson):

• camelCase anchors that were created within section headings, like name="pathItemObject", no longer work, so:
  • they have been removed from the headings
  • uses have been converted e.g. from href="#pathItemObject" to href="#path-item-object"
• anchors that are declared as camelCase outside of headings, like name="dialectSchemaId", still work with href="#dialectSchemaId" and are left alone

You can see the rendered result at https://github.com/handrews/OpenAPI-Specification/tree/anchor-fixes/versions

I've skimmed through these and it looks like the updates are correct. I skimmed slowly enough for 3.1.1 that I am fairly sure nothing else was touched (except trimming a bit of trailing whitespace on some lines, which is fine).