[NFC] Rename _LIBCPP_TYPE_VIS_ONLY to _LIBCPP_TEMPLATE_VIS

The name _LIBCPP_TYPE_VIS_ONLY is no longer accurate because both
_LIBCPP_TYPE_VIS and _LIBCPP_TYPE_VIS_ONLY expand to
__attribute__((__type_visibility__)) with Clang. The only remaining difference
is that _LIBCPP_TYPE_VIS_ONLY can be applied to templates whereas
_LIBCPP_TYPE_VIS cannot (due to dllimport/dllexport not being allowed on
templates).

This patch renames _LIBCPP_TYPE_VIS_ONLY to _LIBCPP_TEMPLATE_VIS.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291035 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/ios b/include/ios
index ea83822..efee39f 100644
--- a/include/ios
+++ b/include/ios
@@ -393,11 +393,11 @@
 _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(io_errc)
 
 template <>
-struct _LIBCPP_TYPE_VIS_ONLY is_error_code_enum<io_errc> : public true_type { };
+struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<io_errc> : public true_type { };
 
 #ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
 template <>
-struct _LIBCPP_TYPE_VIS_ONLY is_error_code_enum<io_errc::__lx> : public true_type { };
+struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<io_errc::__lx> : public true_type { };
 #endif
 
 _LIBCPP_FUNC_VIS
@@ -573,7 +573,7 @@
 }
 
 template <class _CharT, class _Traits>
-class _LIBCPP_TYPE_VIS_ONLY basic_ios
+class _LIBCPP_TEMPLATE_VIS basic_ios
     : public ios_base
 {
 public: