Improve remote block docs for local unix sockets

[mttjohnson]

I was confused when trying to define the remote block for the incus host I want Terraform/OpenTofu to talk to and was using variables to set the values for the remote. While the arguments are optional and some of the defaults are stated I found that the schema value can change how the address argument is used. When the arguments are not present they will use a default value, but I needed the same behavior when an argument was present and contained a value.

I thought it might be useful to provide both an example of a defined local connection to a UNIX socket and a connection to a remote Incus host that would connect over HTTPS.

I also provided a suggestion for updating the description on the address field to indicate how the fields value changes when schema is set to unix.

[mttjohnson]

I was testing this in relation to a pull request on the incus-deploy repo lxc/incus-deploy#16

[maveonair]

Could you please combine the commits into a single one and add a commit message that follows our contribution guidelines?

Here’s an example: docs: Improve remote block for local unix sockets

[mttjohnson]

I updated my branch, combined my changes into a single commit, and updated the commit comment as requested.

[maveonair]

Thanks a lot!