patch 9.1.0201: gM not working correctly with virt text

Problem:  `gM` would include outer virtual text and its padding when
          getting the line length used to calculate the middle of the
          line, putting the cursor much closer to virtual text lines.
Solution: Exclude outer virtual text in getting the line length for
          `gM`, so that virtual text doesn't influence where the cursor
          is moved to (Dylan Thacker-Smith).

closes: #14262

Signed-off-by: Dylan Thacker-Smith <dylan.ah.smith@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/normal.c b/src/normal.c
index 531b6f9..fcd6311 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -6066,7 +6066,7 @@
 	{
 	    oap->motion_type = MCHAR;
 	    oap->inclusive = FALSE;
-	    i = linetabsize(curwin, curwin->w_cursor.lnum);
+	    i = linetabsize_no_outer(curwin, curwin->w_cursor.lnum);
 	    if (cap->count0 > 0 && cap->count0 <= 100)
 		coladvance((colnr_T)(i * cap->count0 / 100));
 	    else