On macOS, Option+Shift+- and Option+- insert an em dash (—) and en dash (–), respectively. On Linux, you can hit the Compose Key and type --- (three hyphens) to get an em dash, or --. (hyphen hyphen period) for an en dash. Windows has some dumb incantation that you'll never remember.

For Windows it's just easier to make a custom keyboard layout and go to town with that: https://www.microsoft.com/en-us/download/details.aspx?id=102...

Alt+0151 or WIN+SHIFT+-, but I can't seem to make the WIN+SHIFT+- combo work in browser, only in a text editor.