pgsql: Clean up some bad grammar and punctuation in description of

Log Message:
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Clean up some bad grammar and punctuation in description of ecpg's decimal
type. Per KOIZUMI Satoru.

Tags:
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REL9_0_STABLE

Modified Files:
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pgsql/doc/src/sgml:
ecpg.sgml (r1.100.2.4 -> r1.100.2.5)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ecpg.sgml?r1=1.100.2.4&r2=1.100.2.5)