csi: let CSI 0 q mean "switch to user configured cursor style"

According to the specs, \E[0 q means a blinking block cursor. However,
since it also states that \E[1 q *also* is a blinking block cursor,
and that it is the default, *and* given that fact that parameter-less
CSIs typically means "reset", let's make it mean "reset to the user
configured cursor style".

main.c

@@ -371,6 +371,7 @@ main(int argc, char *const *argv)
                 conf.colors.bright[7],
             },
         },
+        .default_cursor_style = conf.cursor.style,
         .cursor_style = conf.cursor.style,
         .selection = {
             .start = {-1, -1},