This makes code easier to read and more consistent between C++ and Java.
Also update clang-format settings to always add a line break (even if no braces are used).
std::scoped_lock was introduced in C++17 and is strictly better than
std::lock_guard as it supports locking any number of mutexes safely.
It's also easier to use than std::lock for locking multiple mutexes at
once.
