patch 8.2.0766: display error when using 'number' and 'breakindent'

Problem:    Display error when using 'number' and 'breakindent'.
Solution:   Adjust extra spaces in the first row. (Ken Takata, closes #6089,
            closes #5986)
diff --git a/src/drawline.c b/src/drawline.c
index 8de307a..0a5a4bd 100644
--- a/src/drawline.c
+++ b/src/drawline.c
@@ -1177,6 +1177,12 @@
 		    c_final = NUL;
 		    n_extra = get_breakindent_win(wp,
 				       ml_get_buf(wp->w_buffer, lnum, FALSE));
+		    if (row == startrow)
+		    {
+			n_extra -= win_col_off2(wp);
+			if (n_extra < 0)
+			    n_extra = 0;
+		    }
 		    if (wp->w_skipcol > 0 && wp->w_p_wrap && wp->w_briopt_sbr)
 			need_showbreak = FALSE;
 		    // Correct end of highlighted area for 'breakindent',