folly::AnnotatedLockGuard

Description

Scoped lock for any capability-annotated mutex. std::lock_guard cannot be used in its place because it lacks the scoped_lockable attribute, so the analyzer would not understand that the wrapped capability is held inside the scope. Templated so it works with AnnotatedMutex today and with any future capability-annotated mutex (e.g. an annotated folly::SharedMutex) without needing a parallel guard per type. Use CTAD: folly::AnnotatedLockGuard lock(myMutex);