pgsql: Add backslashes to parentheses in awk regex because if not, they

Log Message:
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Add backslashes to parentheses in awk regex because if not, they are
treated as regex groups.

Modified Files:
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pgsql/src/tools/pgindent:
pgindent (r1.75 -> r1.76)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/pgindent/pgindent.diff?r1=1.75&r2=1.76)