<regex>: Add multiline option and make non-multiline mode the default - #5535

<regex>: Add multiline option and make non-multiline mode the default#5535

Stephan T. Lavavej (StephanTLavavej) merged 7 commits into

microsoft:mainmicrosoft/STL:mainfrom

muellerj2:regex-implement-multiline-optionmuellerj2/STL:regex-implement-multiline-optionCopy head branch name to clipboard