Documentation: upgrade rule() code samples from deprecated outputs attribute

[gregestren]

Description of the bug:

Code samples from https://bazel.build/rules/rules#using_the_validations_output_group include

rule_with_validation = rule(
  implementation = _rule_with_validation_impl,
  outputs = {
...

but according to https://bazel.build/rules/lib/globals#rule, output is deprecated and is disabled with -incompatible_no_rule_outputs_param.

Also for This parameter has been deprecated. Migrate rules to use OutputGroupInfo or attr.output instead., let's link to further details / examples.

Let's have doc examples use current best practices.

What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

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Which operating system are you running Bazel on?

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What is the output of bazel info release?

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If bazel info release returns development version or (@non-git), tell us how you built Bazel.

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What's the output of git remote get-url origin; git rev-parse master; git rev-parse HEAD ?

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Have you found anything relevant by searching the web?

#7977

Any other information, logs, or outputs that you want to share?

No response