[clang] [C++20][Modules] Implement P1857R3 Modules Dependency Discovery (PR #107168)

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@@ -65,7 +65,7 @@ class PragmaAnnotateHandler : public PragmaHandler {
     Token Tok;
     PP.LexUnexpandedToken(Tok);
     if (Tok.isNot(tok::eod))
-      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "#pragma";
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yronglin wrote:

Good catch, it's unecessary, because we have a new `ext_pp_extra_tokens_at_module_directive_eol` for import/module directives. 

https://github.com/llvm/llvm-project/pull/107168