[clang-tools-extra] [Clangd] Don't traverse ConceptDecl in typeForNode (PR #191654)

[Haojian Wu via cfe-commits]

================
@@ -2060,6 +2060,7 @@ static QualType typeForNode(const ASTContext &Ctx, const HeuristicResolver *H,
       QualType VisitTemplateDecl(const TemplateDecl *D) {
         return Visit(D->getTemplatedDecl());
       }
+      QualType VisitConceptDecl(const ConceptDecl *C) { return QualType(); }
----------------
hokein wrote:

how about doing a nullptr check in the above `VisitTemplateDecl()`? 

```
QualType VisitTemplateDecl(const TemplateDecl *D) {
   if (const auto* TD = D->getTemplateDecl())
      return Visit(D->getTemplatedDecl());
   return QualType();
}
```

https://github.com/llvm/llvm-project/pull/191654