pgsql: docs: fix spacing around "if not exists" brackets

[Bruce Momjian]

docs:  fix spacing around "if not exists" brackets

Reported-by: Fabrízio de Royes Mello

Discussion: 
https://postgr.es/m/cafcns+qdd+qkcf8ycpqnjaxown61qy_ydflb3iqqbwclscy...@mail.gmail.com

Author: Fabrízio de Royes Mello

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/3da7502cd00ddf8228c9a4a7e4a08725decff99c

Modified Files
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doc/src/sgml/ref/create_server.sgml       | 2 +-
doc/src/sgml/ref/create_user_mapping.sgml | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)