Update instructions on using ./tools/format.py in README
@@ -125,6 +125,12 @@ submodule. However, you need to install separately:
# Format code.
./tools/format.py
+Before running `./tools/format.py`, make sure you have `yapf` installed for the
+current Python and `rustfmt` for Rust. They can be installed by:
+
+ pip install yapf
+ rustup component add rustfmt-preview
+
Other useful commands:
# Call ninja manually.
