Add grepfruit to developer tools

[enjaku4]

Thanks for contributing to the Ruby Toolbox catalog! <3

Before submitting your pull request:

• If you're referencing a gem by its GitHub repository (e.g. rails/rails), please verify
  that it is not packaged as a Ruby gem. (If it is packaged as a gem, please reference it
  by its gem name instead, e.g. rails.)
• Make sure the CI build passes, we validate your proposed changes in the test suite :)

[enjaku4]

Added new 'Text Search' category under 'Developer Tools', couldn't find an existing category that fit. Included grepfruit and ripgrep to meet the 2-gem minimum.