pgsql: Fix pg_amcheck --skip option parameter handling

Fix pg_amcheck --skip option parameter handling

The skip options set for all-visible and all-frozen were incorrect
as they used space rather than hyphen, causing a syntax error when
invoked. Also, the option for not skipping any pages at all, none,
was documented but not implemented.

Backpatch through 14 where pg_amcheck was introduced.

Bug: #17149
Reported-by: Chen Jiaoqian <chenjq(dot)jy(at)fujitsu(dot)com>
Reviewed-by: Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
Discussion: https://postgr.es/m/[email protected]
Backpatch-through: 14

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/500256d953444628164f0b77ef1ce8c9e05e575f

Modified Files
--------------
src/bin/pg_amcheck/pg_amcheck.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)