Use LLVM as a base for loading a custom style to mimic CLI clang-format's behavior

Author: kkaefer

clang-format/ClangFormatCommand.mm

@@ -142,6 +142,7 @@ - (void)performCommandWithInvocation:(XCSourceEditorCommandInvocation*)invocatio
             // parse style
             llvm::StringRef configString(reinterpret_cast<const char*>(config.bytes),
                                          config.length);
+            clang::format::getPredefinedStyle("LLVM", language, &format);
             auto error = clang::format::parseConfiguration(configString, &format);
             if (error) {
                 completionHandler([NSError