[libc++] Fix typo in documentation for LIBCXX_HERMETIC_STATIC_LIBRARY
[libc++] Fix typo in documentation for LIBCXX_HERMETIC_STATIC_LIBRARY

Thanks to Yichen Yan for the patch.
Differential Revision: https://reviews.llvm.org/D66675

git-svn-id: 756ef344af921d95d562d9e9f9389127a89a6314@369800 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx