pubkey: update comment to reflect location

bitcoin/pubkey.h

@@ -45,7 +45,7 @@ void pubkey_to_der(u8 der[PUBKEY_CMPR_LEN], const struct pubkey *key);
 /* Compare the keys `a` and `b`. Return <0 if `a`<`b`, 0 if equal and >0 otherwise */
 int pubkey_cmp(const struct pubkey *a, const struct pubkey *b);
 
-/* If the two nodes[] are id1 and id2, which index would id1 be? */
+/* If the two pubkeys[] are id1 and id2, which index would id1 be? */
 static inline int pubkey_idx(const struct pubkey *id1, const struct pubkey *id2)
 {
 	return pubkey_cmp(id1, id2) > 0;