rubyzip 3.2: Add type sig for block-form/generic overrides and fix sig top-level config

[gonzedge]

A few of the block-form + generic methods were mistyped on #1022. The ::Zip methods were added as def self. signatures. These two issues were not caught because there was not enough code to exercise the new types; instead I caught them when trying to use gem_rbs_collection again in gonzedge/rambling-trie#90.

This PR:

• fix top level ::Zip module config methods (remove self. and add extend Zip at the top)
• add block-form/generic overrides for Zip::File.open and Zip::File.open_buffer
• add block-form/generic method overrides for Zip::FileSystem::(Dir|File|ZipFileNameMapper)
• add block-form/generic method overrides for Zip::(Input|Output)Stream
• add block-form/generic method overrides for Zip::Streamable*
• add non-block/generic method overrides for Zip::Entry
• add test code for all missing block-form return types
• add more test code to exercise as much code in the library as possible

[github-actions]

@gonzedge Thanks for your contribution!

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See also: https://github.com/ruby/gem_rbs_collection/blob/main/docs/CONTRIBUTING.md

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rubyzip

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[gonzedge]

/merge