[gn build] Port 089227f

Author: llvmgnsyncbot

llvm/utils/gn/secondary/lldb/source/Utility/BUILD.gn

@@ -21,6 +21,7 @@ static_library("Utility") {
     "DataEncoder.cpp",
     "DataExtractor.cpp",
     "Diagnostics.cpp",
+    "DiagnosticsRendering.cpp",
     "Environment.cpp",
     "ErrorMessages.cpp",
     "Event.cpp",