Remove migration of linuxbrew-core formulae

[cho-m]

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Follow up to #21190. We enabled migration over 4 years ago since #12248, which was part of brew 3.3.0. So at least 2 major brew releases have passed and all active Linuxbrew users would have been migrated already.

There are only 25 formulae left so anyone who hasn't migrated can just reinstall formulae if impacted.

[cho-m]

For now, just removed the formulae migration logic.

There is also the git repo migration (i.e. stuff under HOMEBREW_LINUXBREW_CORE_MIGRATION environment variable).

[Copilot]

Pull request overview

This PR removes the legacy linuxbrew-core formulae migration code that has been in place for over 4 years (since Homebrew 3.3.0). The migration logic is no longer needed as all active Linuxbrew users would have migrated already, and the remaining 25 formulae can be manually reinstalled if necessary.

• Deletes the migration constants file containing the list of 25 formulae with special version handling
• Removes shell script logic that triggered and tracked migration status
• Removes Ruby code that performed the actual formula migration by modifying version schemes

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
Library/Homebrew/linuxbrew-core-migration.rb	Complete deletion of migration constants (LINUXBREW_CORE_MIGRATION_OLD_PKG_VERSIONS and LINUXBREW_CORE_MIGRATION_LIST)
Library/Homebrew/cmd/update.sh	Removes git config logic for tracking migration state and condition checks for HOMEBREW_MIGRATE_LINUXBREW_FORMULAE
Library/Homebrew/cmd/update-report.rb	Removes the migration execution logic that modified formula tabs and Settings, plus removes HOMEBREW_MIGRATE_LINUXBREW_FORMULAE from conditional

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[MikeMcQuaid]

Thanks!