patch 9.0.1753: can't move to last non-blank char

Problem: can't move to last non-blank char
Solution: Make g<end> behave like that

Make it possible to move to last non-blank char on a line

We can distinguish between g0 and g^ to move to the very first character
and the first non-blank char.

And while we can move to the last screen char, we cannot go to the last
non-blank screen char.

Since I think g$ is the more widely used and known movement command (and
g<end> is synonymous to it) change the behaviour of g<end> to move to
last non-screen char instead and don't have this be the same command as
the g$ command anymore.

If you want to keep the old behaviour, you can use:

```
nnoremap g<end> g$
```

Add a test to verify the behaviour.

closes: #12593

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/normal.c b/src/normal.c
index 2eb2c38..cbcfd74 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -5821,6 +5821,10 @@
     oparg_T	*oap = cap->oap;
     int		i;
     int		col_off = curwin_col_off();
+    int		flag = FALSE;
+
+    if (cap->nchar == K_END)
+	flag = TRUE;
 
     oap->motion_type = MCHAR;
     oap->inclusive = TRUE;
@@ -5886,6 +5890,13 @@
 	// Make sure we stick in this column.
 	update_curswant_force();
     }
+    if (flag)
+    {
+	do
+	    i = gchar_cursor();
+	while (VIM_ISWHITE(i) && oneleft() == OK);
+	curwin->w_valid &= ~VALID_WCOL;
+    }
 }
 
 /*