gdb: add ATTRIBUTE_PRINTF to complaint_interceptor::issue_complaint

Fix this error when building with clang++-14:

      CXX    complaints.o
    /home/smarchi/src/binutils-gdb/gdb/complaints.c:130:65: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
      g_complaint_interceptor->m_complaints.insert (string_vprintf (fmt, args));
                                                                    ^~~

Change-Id: I0ef11f970510eb8638d1651fa0d5eeecd6a9d31a
1 file changed