Update comment of tzmode [ci skip]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64229 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

time.c

@@ -1632,7 +1632,7 @@ localtimew(wideval_t timew, struct vtm *result)
 PACKED_STRUCT_UNALIGNED(struct time_object {
     wideval_t timew; /* time_t value * TIME_SCALE.  possibly Rational. */
     struct vtm vtm;
-    unsigned int tzmode:3; /* 0:localtime 1:utc 2:fixoff 3:init */
+    unsigned int tzmode:3; /* 0:localtime 1:utc 2:fixoff 3:uninitialized */
     unsigned int tm_got:1;
 });