pgsql: Improve indenting in _hash_pgaddtup

Improve indenting in _hash_pgaddtup

The Assert added in d09dbeb9b came out rather ugly after having run
pgindent on that code.  Here we adjust things to use some local variables
so that the Assert remains within the 80-character margin.

Author: Ted Yu
Discussion: https://postgr.es/m/CALte62wLSir1=x93Jf0xZvHaO009FEJfhVMFwnaR8q=csPP8kQ@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/ec5affdbc283252327e217f99c45574eb63de051

Modified Files
--------------
src/backend/access/hash/hashinsert.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)