Document webpack change: fix: resolve's plugins types

[webpack-bot]

A pull request by @alexander-akait was merged and maintainers requested a documentation change.

See pull request: webpack/webpack#18154

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What kind of change does this PR introduce?

fixes webpack/webpack#18150

Did you add tests for your changes?

Yes

Does this PR introduce a breaking change?

No

What needs to be documented once your changes are merged?

Yes, resolve.plugins types should be updated