patch 8.2.0943: displaying ^M or ^J depends on current buffer

Problem:    Displaying ^M or ^J depends on current buffer.
Solution:   Pass the displayed buffer to transchar(). (closes #6225)
diff --git a/src/drawline.c b/src/drawline.c
index 0a5a4bd..9d65aa4 100644
--- a/src/drawline.c
+++ b/src/drawline.c
@@ -1764,7 +1764,7 @@
 			    {
 				// head byte at end of line
 				mb_l = 1;
-				transchar_nonprint(extra, c);
+				transchar_nonprint(wp->w_buffer, extra, c);
 			    }
 			    else
 			    {
@@ -2224,7 +2224,7 @@
 		}
 		else if (c != NUL)
 		{
-		    p_extra = transchar(c);
+		    p_extra = transchar_buf(wp->w_buffer, c);
 		    if (n_extra == 0)
 			n_extra = byte2cells(c) - 1;
 #ifdef FEAT_RIGHTLEFT