chore: fix typo recommentd => recommend in bin/init_new_gem

[sanfrecce-osaka]

I noticed typo on executing bin/init_new_gem, So I fixed it.

- puts "We recommentd to add your account to maintain the RBS actively."
+ puts "We recommend to add your account to maintain the RBS actively."

[github-actions]

@sanfrecce-osaka 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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You changed non-gem files.

@pocke, please review and approve the changes.