The signatures of functions in these PRs should be more standard: #27342, #25510, #20936, including the following: ipv4numtostring, ipv4stringtonum, ipv4stringtonumordefault, ipv4stringtonumornull, ipv6numtostring. This PR will add necessary underscores between the words of each of them, like changing ipv4numtostring to ipv4_num_to_string.