Another patch for consideration related to the first in this thread,
I've confirmed that clients can signal to servers that they are willing
to accept server initiated progress notifications with the client
capability in the attached patch. 

Note: there is still no server capability for this that can be ignored,
and the `eglot-report-progress` defcustom remains relevant here. Any
server initiated progress report will be ignored if
`eglot-report-progress` is `nil`.

Server will send a `window/workDoneProgress/create` request, but nothing
needs to be done with it. That request will be followed by the already
implemented $/progress notifications.

I need to find a server that I can test this with before this patch is
applied. I will report back in this thread once I've done that.

-- 
Danny Freeman