pgsql: Remove some comments related to pqPipelineSync() and PQsendPipel

Remove some comments related to pqPipelineSync() and PQsendPipelineSync()

These comments explained how these functions behave internally, and the
equivalent is described in the documentation section dedicated to the
pipeline mode of libpq.  Let's remove these comments, getting rid of the
duplication with the docs.

Reported-by: Álvaro Herrera
Reviewed-by: Álvaro Herrera
Discussion: https://postgr.es/m/202401150949.wq7ynlmqxphy@alvherre.pgsql

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/061cc7eacac15c4bcd4447a238e16a6e0ea9c6bb

Modified Files
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src/interfaces/libpq/fe-exec.c | 17 -----------------
1 file changed, 17 deletions(-)