Add new term warning and update terms
What does this MR do and why?
Update the SubstitutionWarning.yml
file to include the recommended use of "sign in" instead of "log-in" or "log in".
Docs link: Recommended word list
Slack discussion link: https://gitlab.slack.com/archives/CDWGE0DDY/p1722266203321919
Edited by Brendan Lynch