Broken cross-ref links in various docs

[bryevdv]

Several package docs at https://azure.github.io/azure-sdk-for-python/ have cross-references to classes that do not render properly, e.g.:

• https://azure.github.io/azure-sdk-for-python/ref/azure.eventhub.html#azure.eventhub.consumer.EventHubConsumer.receive

• https://azure.github.io/azure-sdk-for-python/ref/azure.servicebus.html#azure.servicebus.servicebus_client.ServiceBusClient.get_queue

• https://azure.github.io/azure-sdk-for-python/ref/azure.storage.queue.html#azure.storage.queue.queue_client.QueueClient.create_queue

• https://azure.github.io/azure-sdk-for-python/ref/azure.keyvault.secrets.html#azure.keyvault.secrets.client.SecretClient.backup_secret

(This list is not exhaustive, just specific examples in different packages)

I made a small PR to fix this in keyvault: #7215 using explicit directives:

:class:`~foo.Bar`

etc. But noted that although things work with this change, the rendered appearance is also different from the "implicitly" rendered cross reference links (I guess these are generated by sphinx-apidoc?) i.e.

VS

The second version is the version with explicit :class: (though without a leading tilde to shorten) and is apparently used already in some SDKs. I am not sure how else to fix this problem except to use explicit directives, and FWIW I have only ever used explicit directives in the past.

[chlowell]

My belief (may well be incorrect) is that tildes backticks control the rendered style. So in your penultimate screenshot, I infer the link was "~foo.Pipeline", and that "`~foo.Pipeline`" would have rendered with the same style as your final screenshot.

[bryevdv]

The tildes control whether the full dotted path is displayed or not. So

:class:`foo.bar.Baz`  ==> "foo.bar.Baz"

but 

:class:`~foo.bar.Baz` ==> "Baz"

The difference between the last two that I am specifically referring to is the "plain text" blue link (which is how the implicit cross refs seem to render everywhere) vs the "outlined" fixed width text link (which is how the explicit :class: version renders everywhere).

[chlowell]

Sorry, I meant "backticks" when I wrote "tildes".

[bryevdv]

Oh, no adding just backticks without the :class: in front just renderers the same broken link text, only italicized (I tried, just as an experiment). Also, most of the working implicit cross ref links don't have backticks at all

[bryevdv]

Also, AFAIK, single backticks don't actually do much useful, so I have been surprised to see them so much. If you want fixed-width <pre> kind of text, that takes double backticks:

backquotes: ``text`` for code samples.

[xiangyan99]

Looks like it is fixed.