README should mention about Go telemetry

[dolmen]

README should mention if Go telemetry is enabled by default or not, and tell commands for how to enable telemetry if one wants it.

[tianon]

Whatever the defaults for the upstream toolchain are, that's what our settings are (except for really exceptional cases like #472, which we generally try very hard to avoid).

[dolmen]

What about telling how to enable telemetry and its upload?
(If ever telemetry results on short lived containers is useful to the Go team)

[tianon]

Now that telemetry has shipped in Go 1.23 (local-only by default, only submits to upstream with opt-in via explicit invocation of go telemetry on), I've been following the discussion around easier ways to disable telemetry completely (golang/go#68960), and it sounds like easier ways to enable telemetry are very firmly in the Not Planned category, possibly even as far as Not Possible (given the design of the telemetry reporting feature; golang/go#68960 (comment)).