"Backends" and "Class availability" chapters desing

[PetroBondar]

Currently, the Backends, Generic vs non-generic SYCL, and Class availability chapters are not represented in the Reference Guide.

We propose to add it with the following structure (on the higher level of hierarchy):

• Backends (4.1. Backends and 4.2. Generic vs non-generic SYCL)
• Class availability (4.4. Class availability)

Those chapters will appear sequentially after "Namespaces" in the contents bar.

Could you please review and provide your opinion and recommendations for those chapters?
We will create PR after a discussion.

[mkinsner]

For "Generic vs non-generic SYCL" and "Class availablilty", I think placing after "Namespaces" is fine. Backends probably make more sense further down the list. Can we put "Backends" after "I/O"/"Streams"?

[PetroBondar]

Thanks for the comment!
If I understood correctly, you propose a structure update that looks like this:

• ...
• Namespaces (implemented)
• Generic vs non-generic SYCL (4.2. Generic vs non-generic SYCL)
• Class availability (4.4. Class availability)
• .... (implemented parts)
• Backends (4.1. Backends)
• IO (implemented)

Please correct me if I'm wrong.

If everything is correct, then this structure looks good to me.

[PetroBondar]

Created PR: #132