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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REL9_5_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/ebd194ac58f8df3620d17bc5f1824f9833794b98

Modified Files
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src/backend/utils/adt/geo_ops.c | 13 ++++++++-----
src/test/regress/expected/circle.out | 10 +++++-----
src/test/regress/sql/circle.sql | 10 +++++-----
3 files changed, 18 insertions(+), 15 deletions(-)