[clangd] Adapt API change after 342451.

llvm-svn: 342452
diff --git a/clang-tools-extra/clangd/FindSymbols.cpp b/clang-tools-extra/clangd/FindSymbols.cpp
index 054e63d..0b00012 100644
--- a/clang-tools-extra/clangd/FindSymbols.cpp
+++ b/clang-tools-extra/clangd/FindSymbols.cpp
@@ -270,8 +270,9 @@
   IndexOpts.SystemSymbolFilter =
       index::IndexingOptions::SystemSymbolFilterKind::DeclarationsOnly;
   IndexOpts.IndexFunctionLocals = false;
-  indexTopLevelDecls(AST.getASTContext(), AST.getLocalTopLevelDecls(),
-                     DocumentSymbolsCons, IndexOpts);
+  indexTopLevelDecls(AST.getASTContext(), AST.getPreprocessor(),
+                     AST.getLocalTopLevelDecls(), DocumentSymbolsCons,
+                     IndexOpts);
 
   return DocumentSymbolsCons.takeSymbols();
 }