Abseil Mutex uses Lock and Unlock, rather than lock and unlock

As the title says, Abseil's absl::Mutex uses capitalized Lock() and Unlock(), rather than lock() and unlock(). This was a rather annoying find while I was benchmarking various different mutex implementations with parallel_flat_hash_map.

I was testing with Abseil version 20211102.0 via Conan. I didn't check how far back the capitalization change originates from.

If needed, here's a snippet from GCC11:

/parallel_hashmap/phmap_base.h:4816:17: error: ‘using mutex_type = class absl::lts_20211102::Mutex’ {aka ‘class absl::lts_20211102::Mutex’} has no member named ‘lock’; did you mean ‘Lock’?
 4816 |             m_->lock();
      |             ~~~~^~~~
      |             Lock

greg7mdp / parallel-hashmap

Abseil Mutex uses Lock and Unlock, rather than lock and unlock #147