[clang-tools-extra] [clangd] Re-land "support outgoing calls in call hierarchy" (PR #117673)

[kadir çetinkaya via cfe-commits]

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@@ -163,7 +163,7 @@ class Checker {
   unsigned ErrCount = 0;
 
   Checker(llvm::StringRef File, const ClangdLSPServer::Options &Opts)
-      : File(File), Opts(Opts) {}
+      : File(File), Opts(Opts), Index(/*SupportContainedRefs=*/false) {}
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kadircet wrote:

why false here? i think it's better if we use whatever clangd-server's default is

https://github.com/llvm/llvm-project/pull/117673