pgsql: Fix circle_in to accept "(x,y),r" as it's advertised to do.

Fix circle_in to accept "(x,y),r" as it's advertised to do.

Our documentation describes four allowed input syntaxes for circles,
but the regression tests tried only three ... with predictable
consequences. Remarkably, this has been wrong since the circle
datatype was added in 1997, but nobody noticed till now.

David Zhang, with some help from me

Discussion: https://postgr.es/m/332c47fa-d951-7574-b5cc-a8f7f7201202@highgo.ca

Branch
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REL_12_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/35d1eefb29d03d5a85f71038679f1f8a14358255

Modified Files
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src/backend/utils/adt/geo_ops.c | 13 ++++++++-----
src/test/regress/expected/circle.out | 8 ++++----
src/test/regress/sql/circle.sql | 8 ++++----
3 files changed, 16 insertions(+), 13 deletions(-)