Change comment to say hidden instead of internal visibility

Author: fsfod

clang/include/clang/Support/Compiler.h

@@ -18,7 +18,7 @@
 
 /// CLANG_ABI is the main export/visibility macro to mark something as
 /// explicitly exported when clang is built as a shared library with everything
-/// else that is unannotated having internal visibility.
+/// else that is unannotated having hidden visibility.
 ///
 /// CLANG_EXPORT_TEMPLATE is used on explicit template instantiations in source
 /// files that were declared extern in a header. This macro is only set as a