pgsql: Further -Wshadow=compatible-local warning fixes

Further -Wshadow=compatible-local warning fixes

These should have been included in 421892a19 as these shadowed variable
warnings can also be fixed by adjusting the scope of the shadowed variable
to put the declaration for it in an inner scope.

This is part of the same effort as f01592f91.

By my count, this takes the warning count from 114 down to 106.

Author: David Rowley and Justin Pryzby
Discussion: https://postgr.es/m/CAApHDvrwLGBP%2BYw9vriayyf%3DXR4uPWP5jr6cQhP9au_kaDUhbA%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/f959bf9a5b9cecd2f6e6bdd24a34a7b269b00827

Modified Files
--------------
src/backend/access/spgist/spgdoinsert.c | 3 ++-
src/backend/commands/trigger.c          | 2 +-
src/backend/executor/nodeHash.c         | 3 +--
src/backend/optimizer/plan/planner.c    | 2 +-
src/backend/tsearch/ts_typanalyze.c     | 3 ++-
src/backend/utils/adt/levenshtein.c     | 6 +++---
src/backend/utils/adt/rangetypes_gist.c | 5 +++--
src/backend/utils/adt/ruleutils.c       | 3 ++-
8 files changed, 15 insertions(+), 12 deletions(-)