message: textDocument/signatureHelp: enable documentation
diff: @@ -91,10 +91,8 @@ public:
  const char *ret_type = nullptr;
  SignatureInformation &ls_sig = ls_sighelp.signatures.emplace_back();
  -#if LLVM_VERSION_MAJOR >= 8
  const RawComment *RC = getCompletionComment(S.getASTContext(), Cand.getFunction());
  ls_sig.documentation = RC ? RC->getBriefText(S.getASTContext()) : "";
  -#endif
  for (const auto &Chunk : *CCS)
  switch (Chunk.Kind) {
  case CodeCompletionString::CK_ResultType:
  @@ -171,7 +169,7 @@ void MessageHandler::textDocument_signatureHelp(
  CodeCompleteOptions CCOpts;
  CCOpts.IncludeGlobals = false;
  CCOpts.IncludeMacros = false;
  - CCOpts.IncludeBriefComments = false;
  + CCOpts.IncludeBriefComments = true;
  if (cache.IsCacheValid(path, begin_pos)) {
  SignatureHelpConsumer Consumer(CCOpts, true);
  cache.WithLock([&]() { Consumer.ls_sighelp = cache.result; });
  