Implement P0482R2, support for char8_t type.

This is not yet part of any C++ working draft, and so is controlled by the flag
-fchar8_t rather than a -std= flag. (The GCC implementation is controlled by a
flag with the same name.)

This implementation is experimental, and will be removed or revised
substantially to match the proposal as it makes its way through the C++
committee.

llvm-svn: 331244
diff --git a/clang/lib/Format/FormatToken.cpp b/clang/lib/Format/FormatToken.cpp
index 10ac392..c63f012 100644
--- a/clang/lib/Format/FormatToken.cpp
+++ b/clang/lib/Format/FormatToken.cpp
@@ -57,6 +57,7 @@
   case tok::kw_bool:
   case tok::kw___underlying_type:
   case tok::annot_typename:
+  case tok::kw_char8_t:
   case tok::kw_char16_t:
   case tok::kw_char32_t:
   case tok::kw_typeof: