Update CONTRIBUTING.md to use RustRover instead of IntelliJ Rust (#15448)

JetBrains has transitioned from the IntelliJ Rust plugin to RustRover as
their dedicated Rust IDE. This updates the documentation to reflect this
change while maintaining backward compatibility with the existing `cargo
dev setup intellij` command.

Changes:
- Replace IntelliJ Rust references with RustRover in CONTRIBUTING.md
- Update links to point to official RustRover homepage
- Update development guide in book/src/development/basics.md
- Keep existing command names for backward compatibility

**Question**: Do we also need to change the `intellij` command to
`rustrover`?

fixes rust-lang/rust-clippy#15406

changelog: Update CONTRIBUTING.md to reference RustRover instead of
deprecated IntelliJ Rust

0 files changed, 0 insertions, 0 deletions