out of date comment in commit_ts.c

Hi hackers,

I noticed that commit_ts.c has the following comment:

 * XLOG interactions: this module generates an XLOG record whenever a new
 * CommitTs page is initialized to zeroes.  Also, one XLOG record is
 * generated for setting of values when the caller requests it; this allows
 * us to support values coming from places other than transaction commit.
 * Other writes of CommitTS come from recording of transaction commit in
 * xact.c, which generates its own XLOG records for these events and will
 * re-perform the status update on redo; so we need make no additional XLOG
 * entry here.

IIUC the ability for callers to request WAL record generation is no longer
possible as of 08aa89b [0].  Should the second sentence be removed?

[0] https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=08aa89b

-- 
Nathan Bossart
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