patch 8.2.1547: various comment problems

Problem:    Various comment problems.
Solution:   Update comments.
diff --git a/src/map.c b/src/map.c
index 26fce68..dd3139d 100644
--- a/src/map.c
+++ b/src/map.c
@@ -1952,7 +1952,7 @@
 	// when they are read back.
 	if (c == K_SPECIAL && what != 2)
 	{
-	    modifiers = 0x0;
+	    modifiers = 0;
 	    if (str[1] == KS_MODIFIER)
 	    {
 		modifiers = str[2];