pgsql: Change Graphviz file extension

Change Graphviz file extension

Change extension for Graphviz files from .dot to .gv.  The latter
appears to be the generally preferred one nowadays.

Discussion: https://www.postgresql.org/message-id/flat/71fe76d2-c7d7-2acc-6762-bbf9e61c566e%402ndquadrant.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/41205719d34969018f708baa70d9d06dae0c0d08

Modified Files
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contrib/pg_trgm/trgm_regexp.c           | 14 +++++++-------
doc/src/sgml/images/Makefile            |  2 +-
doc/src/sgml/images/{gin.dot => gin.gv} |  0
3 files changed, 8 insertions(+), 8 deletions(-)