Navigator.plugins, mimeTypes, pdfViewerEnabled updates

[hamishwillee]

This is first part of work for https://bugzilla.mozilla.org/show_bug.cgi?id=1720353

This adds docs for Navigator.pdfViewerEnabled, which is the new say to test whether inline viewing of PDF files is supported when you click on a PDF file link.

In addition there are some deprecated properties Navigator.plugins and Navigator.mimeTypes that were/are used by sites to feature test for PDF viewer support. However the method is unreliable, because they tend to check only a couple of plugins, and also gives out some info that can be used for fingerprinting. So the spec also hard codes the output to be some of the strings that the old code typically uses for feature checking IFF PDF viewing is supported, or nothing if it is not - ie it mirrors the new property in the old properties.
This is no great loss since this is about all they were being use for other than flash, which is also highly discommended.

Other docs work can be tracked in #13370

[hamishwillee]

Thanks @jpmedley - I've accepted all your suggestions (with answers to questions embedded, where relevant). Ready for re-review.

[jpmedley]

Apologies. This is needed to make one of the tests pass.

Merged the requested change

[hamishwillee]

Not your fault. The filename was upper cased. Fixed now.

[github-actions]

Preview URLs

• https://pr13605.content.dev.mdn.mozit.cloud/en-US/docs/Web/API/Navigator/mimeTypes
• https://pr13605.content.dev.mdn.mozit.cloud/en-US/docs/Web/API/Navigator/pdfViewerEnabled
• https://pr13605.content.dev.mdn.mozit.cloud/en-US/docs/Web/API/Navigator/plugins
• https://pr13605.content.dev.mdn.mozit.cloud/en-US/docs/Web/API/Navigator

Flaws

URL: /en-US/docs/Web/API/Navigator
Title: Navigator
on GitHub
Flaw count: 5

• macros:
  • wrong xref macro used (consider changing which macro you use)
  • /en-US/docs/Web/API/Navigator/securitypolicy does not exist
  • /en-US/docs/Web/API/Navigator/standalone does not exist
• bad_bcd_links:
  • no explanation!
  • no explanation!

---

URL: /en-US/docs/Web/API/Navigator/mimeTypes
Title: Navigator.mimeTypes
on GitHub
Flaw count: 2

• macros:
  • wrong xref macro used (consider changing which macro you use)
  • wrong xref macro used (consider changing which macro you use)

---

URL: /en-US/docs/Web/API/Navigator/plugins
Title: Navigator.plugins
on GitHub
Flaw count: 2

• macros:
  • wrong xref macro used (consider changing which macro you use)
  • wrong xref macro used (consider changing which macro you use)

---

URL: /en-US/docs/Web/API/Navigator/pdfViewerEnabled
Title: Navigator.pdfViewerEnabled
on GitHub
Flaw count: 2

• macros:
  • wrong xref macro used (consider changing which macro you use)
  • wrong xref macro used (consider changing which macro you use)

External URLs

URL: /en-US/docs/Web/API/Navigator
Title: Navigator
on GitHub

No new external URLs

---

URL: /en-US/docs/Web/API/Navigator/mimeTypes
Title: Navigator.mimeTypes
on GitHub

No new external URLs

---

URL: /en-US/docs/Web/API/Navigator/plugins
Title: Navigator.plugins
on GitHub

No new external URLs

---

URL: /en-US/docs/Web/API/Navigator/pdfViewerEnabled
Title: Navigator.pdfViewerEnabled
on GitHub

No new external URLs

[hamishwillee]

@jpmedley I think the updates I made here cleared your approval.