Folks who follow the changes in the Publication Manual of the American Psychological Association learned last year (2020) that “APA style” now recommends a single space after sentence-ending punctuation. Woohoo!
Section 6.1 in the seventh edition of the manual expessly states, “[i]nsert one space after the following:” and then includes as the first bullet in a catalog of bulleted item, “periods of other puntuation marks at the end of a sentence” (p. 154). So, there we have it.
American Psychological Association. (2020). Publication manual (7th ed.). Author.