add githooks and format

githooks/pre-commit

+#!/usr/bin/env bash
+
+set -e
+
+REPO_ROOT_DIR="$(git rev-parse --show-toplevel)"
+
+files=$((git diff --cached --name-only --diff-filter=ACMR | grep -Ei "\.rs$") || true)
+if [ ! -z "${files}" ]; then
+    cargo fmt --all
+    git add $(echo "$files" | paste -s -d " " -)
+fi
+

src/main.rs

-fn main() {
-}
+fn main() {}

traits/src/lib.rs

 #![cfg_attr(not(feature = "std"), no_std)]
 
-pub trait MultiCurrency {
-
-}
+pub trait MultiCurrency {}