Update src/asm_files.cpp

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

src/asm_files.cpp

@@ -246,7 +246,7 @@ static void append_subprograms(raw_program& prog, const vector<raw_program>& pro
             auto [symbol_name, section_index] =
                 get_symbol_name_and_section_index(symbols, reloc.relocation_entry_index);
             if (section_index >= reader.sections.size()) {
-                throw UnmarshalError("Invalid section index at source offset " +
+                throw UnmarshalError("Invalid section index " + std::to_string(section_index) + " at source offset " +
                                      std::to_string(reloc.source_offset));
             }
             ELFIO::section& subprogram_section = *reader.sections[section_index];