This behaviour is controlled by the following option:
Settings/PreferencesEditor | Code Style | TypeScript"Punctuation" tab | Generated code -> Quote marks
As of 2017.1 version it’s on new Punctuation tab and options are named a bit differently:

This behaviour is controlled by the following option:
Settings/PreferencesEditor | Code Style | TypeScript"Punctuation" tab | Generated code -> Quote marksAs of 2017.1 version it’s on new Punctuation tab and options are named a bit differently:
