pgsql: Suppress "may be used uninitialized" warnings from older compile

Suppress "may be used uninitialized" warnings from older compilers.

The "children" list won't be used until "got_children" has been set
true, but older compilers don't get that; about half a dozen
buildfarm animals are warning about this. Issue added by 11ff192b5.

While here, improve slightly-shaky grammar in comment.

Discussion: /messages/by-id/2057835.1744833309@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/fc5e966f73f06ab2b3e7fa488fc2712d77639947

Modified Files
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src/backend/commands/tablecmds.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)