patch 8.1.0212: preferred cursor column not set in interfaces

Problem:    Preferred cursor column not set in interfaces.
Solution:   Set w_set_curswant when setting the cursor. (David Hotham,
            closes #3060)
diff --git a/src/if_py_both.h b/src/if_py_both.h
index 58db254..459bc50 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -3985,6 +3985,7 @@
 
 	self->win->w_cursor.lnum = lnum;
 	self->win->w_cursor.col = col;
+	self->win->w_set_curswant = TRUE;
 #ifdef FEAT_VIRTUALEDIT
 	self->win->w_cursor.coladd = 0;
 #endif