patch 9.0.2032: cannot get mouse click pos for tab or virt text

Problem:  Cannot accurately get mouse clicking position when clicking on
          a TAB or with virtual text.
Solution: Add a "coladd" field to getmousepos() result.

closes: #13335

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>
diff --git a/src/beval.c b/src/beval.c
index cd91863..65dfbc2 100644
--- a/src/beval.c
+++ b/src/beval.c
@@ -74,7 +74,7 @@
 	    }
 	}
 
-	col = vcol2col(wp, lnum, col);
+	col = vcol2col(wp, lnum, col, NULL);
 	scol = col;
 
 	if (VIsual_active