pgsql: Fix recent accidental omission in pg_proc.dat

Fix recent accidental omission in pg_proc.dat

ed1a88dda added support functions for the ntile(), percent_rank() and
cume_dist() window functions but neglected to actually add these support
functions to the pg_proc entry for the corresponding window function.

Also, take this opportunity to add these window functions to one of the
regression tests added in ed1a88dda to give the support functions a little
bit of exercise. If I'd done that in the first place then the omission
would have been more obvious.

Bump the catversion, again.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/b5aff9255700b0b3155a4d2be865b6a776c2bda4

Modified Files
--------------
src/include/catalog/catversion.h | 2 +-
src/include/catalog/pg_proc.dat | 14 ++++++++------
src/test/regress/expected/window.out | 8 +++++++-
src/test/regress/sql/window.sql | 8 +++++++-
4 files changed, 23 insertions(+), 9 deletions(-)