doc: +nightly not needed anymore for git commit hook.

doc/src/development.md

@@ -35,13 +35,13 @@ the current date, and a new section above is created.
 ## cargo fmt pre-commit hook
 
 To ensure every contributor uses the same code style, make sure
-you run `cargo +nightly fmt` before committing. You can force yourself
+you run `cargo fmt` before committing. You can force yourself
 to do this by creating a git `pre-commit` hook like the following:
 
 ```shell
 #!/bin/sh
-if ! cargo +nightly fmt -- --check >/dev/null; then
-    echo "There are some code style issues. Run 'cargo +nightly fmt' to fix it."
+if ! cargo fmt -- --check >/dev/null; then
+    echo "There are some code style issues. Run 'cargo fmt' to fix it."
     exit 1
 fi