Clarify default behaviour in README for no-commit-to-branch

Author: mjay-taskize

README.md

@@ -80,7 +80,7 @@ Add this to your `.pre-commit-config.yaml`
     - Use `args: ['--django']` to match `test*.py` instead.
 - `no-commit-to-branch` - Protect specific branches from direct checkins.
     - Use `args: [--branch, staging, --branch, master]` to set the branch.
-      `master` is the default if no argument is set.
+      `master` is the default if no branch argument is set.
     - `-b` / `--branch` may be specified multiple times to protect multiple
       branches.
     - `-p` / `--pattern` can be used to protect branches that match a supplied regex