pgsql: Formatting cleanup in ecpglib/prepare.c.

Formatting cleanup in ecpglib/prepare.c.

Looking at this code made my head hurt.  Format the comments more
like the way it's done elsewhere, break a few overly long lines.
No actual code changes in this commit.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/92dff341160ae896dcfff2dac59fd0c860892f26

Modified Files
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src/interfaces/ecpg/ecpglib/prepare.c | 99 ++++++++++++++++++++---------------
1 file changed, 56 insertions(+), 43 deletions(-)