[docs] Replace non-existent LLVM_YAML_UNIQUE_TYPE() macro

LLVM_YAML_STRONG_TYPEDEF() is the correct macro to perform this function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183280 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed