Replace "fallthrough" comments with LLVM_FALLTHROUGH

This is a mechanical change of comments in switches like fallthrough,
fall-through, or fall-thru to use the LLVM_FALLTHROUGH macro instead.

llvm-svn: 278902

llvm/lib/Object/SymbolicFile.cpp

@@ -36,7 +36,7 @@ Expected<std::unique_ptr<SymbolicFile>> SymbolicFile::createSymbolicFile(
   case sys::fs::file_magic::bitcode:
     if (Context)
       return errorOrToExpected(IRObjectFile::create(Object, *Context));
-  // Fallthrough
+    LLVM_FALLTHROUGH;
   case sys::fs::file_magic::unknown:
   case sys::fs::file_magic::archive:
   case sys::fs::file_magic::macho_universal_binary: