formula: dedupe link_overwrite_formulae across aliases

[p-linnane]

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Claude Code Opus 4.7 was used to create the test.

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When I installed openssl@4 today, I was presented with this warning:

Warning: openssl@4 was installed but not linked because openssl@3 and openssl@3 are already linked.

After this change:

Warning: openssl@4 was installed but not linked because openssl@3 is already linked.

Formula#link_overwrite_formulae_names can include both an alias (openssl) and its canonical name (openssl@3) as distinct strings that resolve to the same Formula via Formula[], so the sentence ends up listing it twice. Dedupe by full_name after resolving names to formulae.

[Copilot]

Pull request overview

This PR fixes duplicated entries in Formula#link_overwrite_reason warnings when link_overwrite_formulae_names contains both an alias and a canonical name that resolve to the same formula, by deduplicating after resolution.

Changes:

• Deduplicate link_overwrite_formulae results by full_name after resolving names to Formula instances.
• Add a unit test asserting alias/canonical-name resolution does not produce duplicate formulae in link_overwrite_formulae.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
Library/Homebrew/formula.rb	Dedupes resolved overwrite formulae via uniq(&:full_name) to prevent duplicate warnings.
Library/Homebrew/test/formula_spec.rb	Adds a regression test for deduplication when alias and canonical names map to the same formula.

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[ZhongRuoyu]

Thanks!

[MikeMcQuaid]

Thanks!