patch 8.1.0579: cannot attach properties to text

Problem:    Cannot attach properties to text.
Solution:   First part of adding text properties.
diff --git a/src/ex_getln.c b/src/ex_getln.c
index bfda942..4ea8bfa 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -769,6 +769,21 @@
 		    stuffcharReadbuff(*c);
 		    *c = '\\';
 		}
+#ifdef FEAT_MBYTE
+		// add any composing characters
+		if (mb_char2len(*c) != mb_ptr2len(ml_get_cursor()))
+		{
+		    int save_c = *c;
+
+		    while (mb_char2len(*c) != mb_ptr2len(ml_get_cursor()))
+		    {
+			curwin->w_cursor.col += mb_char2len(*c);
+			*c = gchar_cursor();
+			stuffcharReadbuff(*c);
+		    }
+		    *c = save_c;
+		}
+#endif
 		return FAIL;
 	    }
 	}