fix: make FindMangledSymbol private

Author: Nerixyz

lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.h

@@ -141,7 +141,6 @@ class SymbolFileNativePDB : public SymbolFileCommon {
   std::optional<PdbCompilandSymId> FindSymbolScope(PdbCompilandSymId id);
 
   std::optional<llvm::StringRef> FindMangledFunctionName(PdbCompilandSymId id);
-  std::optional<llvm::StringRef> FindMangledSymbol(SegmentOffset so);
 
   void FindTypes(const lldb_private::TypeQuery &match,
                  lldb_private::TypeResults &results) override;
@@ -272,6 +271,8 @@ class SymbolFileNativePDB : public SymbolFileCommon {
   void CacheUdtDeclarations();
   llvm::Expected<Declaration> ResolveUdtDeclaration(PdbTypeSymId type_id);
 
+  std::optional<llvm::StringRef> FindMangledSymbol(SegmentOffset so);
+
   llvm::BumpPtrAllocator m_allocator;
 
   lldb::addr_t m_obj_load_address = 0;