Support 'homepage' field of Cargo.toml and package.json

[rhysd]

Make sure these boxes are checked! 📦✅

• You have the latest version of rustfmt installed

$ rustup component add rustfmt-preview --toolchain nightly

• You ran cargo fmt on the code base before submitting
• You reference which issue is being closed in the PR text
  • I searched 'homepage' word but no open issue was found

Both Cargo.toml and package.json have homepage field. They are meaning the same so I thought homepage field should be copied from Cargo.toml into package.json. This patch implements the feature.

• Cargo.toml
  • https://doc.rust-lang.org/cargo/reference/manifest.html
• package.json
  • https://docs.npmjs.com/files/package.json#homepage

[ashleygwilliams]

thank you so much!