cmd/go: go help packages is out of date

[rogpeppe]

What version of Go are you using (go version)?

$ go version
go version devel go1.20-119f679a3b Thu Jan 5 19:33:00 2023 +0000 linux/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

N/A

What did you do?

go help packages

What did you expect to see?

Documentation explaining how to specify package paths in the usual mode that the go command is used (module mode).

What did you see instead?

Paragraphs like this, which apply only in GOPATH mode
with apparently no explanation of what the behaviour is in module mode:

Otherwise, the import path P denotes the package found in
the directory DIR/src/P for some DIR listed in the GOPATH
environment variable (For more details see: 'go help gopath').

• "all" expands to all packages found in all the GOPATH
  trees. For example, 'go list all' lists all the packages on the local
  system. When using modules, "all" expands to all packages in
  the main module and their dependencies, including dependencies
  needed by tests of any of those.

An import path is a pattern if it includes one or more "..." wildcards,
each of which can match any string, including the empty string and
strings containing slashes. Such a pattern expands to all package
directories found in the GOPATH trees with names matching the
patterns.

Looks like an update is needed.

[gopherbot]

Change https://go.dev/cl/462288 mentions this issue: cmd/go/help: update package long description base on go module