Fix -Wparentheses warning. NFCI.

llvm-svn: 362491
diff --git a/clang-tools-extra/clangd/Protocol.cpp b/clang-tools-extra/clangd/Protocol.cpp
index 5c5912e..4714c6c 100644
--- a/clang-tools-extra/clangd/Protocol.cpp
+++ b/clang-tools-extra/clangd/Protocol.cpp
@@ -832,8 +832,8 @@
 }
 
 llvm::json::Value toJSON(const ParameterInformation &PI) {
-  assert(PI.labelOffsets.hasValue() ||
-         !PI.labelString.empty() && "parameter information label is required");
+  assert((PI.labelOffsets.hasValue() || !PI.labelString.empty()) &&
+         "parameter information label is required");
   llvm::json::Object Result;
   if (PI.labelOffsets)
     Result["label"] =