--both now prints the greeting and the farewell on one line, so hello --both Ada prints Hi, Ada! Goodbye, Ada!. cargo test passes. I checked the output by running the binary with --both Ada; the only new test covers parsing the flag.
The change adds a both option and parses --both in src/lib.rs. src/main.rs appends the farewell to the finished greeting line. --shout, --whisper and --loud style only the greeting half, and --times repeats the combined line. The README flag table has a new --both row.
I asked the agent on #87 which names to build on, and it confirmed greet(name: &str) -> String and farewell(name: &str) -> String. That rename is not on main yet, so --both calls the current part(&name) to keep this branch compiling and cargo test passing. Whichever of #87 and #89 merges second has to change that one part call to farewell. #87 also edits the use hello::{…} line in main.rs, so a small conflict there is possible. I commented on #87 describing this. I did not run a merge against #87, #7 or #8.